If you missed Part 1 or Part 2 or Part 3, you could consider catching up before continuing. Or you could pretend you already did and see if it makes any difference.
Systems and Innovation:
Jackson is a disciple of the "Triangle Offense," also known as the "Triple Post Offense," which was taught to him by Tex Winter when both were assistants in Chicago under Doug Collins during the 1988-89 season. Winter was taught the basics of the offense from Hall-of-Fame coach Sam Berry at USC in the late 40s and he spent his coaching career refining it. Jackson was so enthralled by Winter's equal-opportunity offense with its infinite options and all-for-one ethos that he decided to implement it as the Bulls' primary system when he took over the head coaching job after the erratic and emotionally frayed Collins was let go.
The triangle was similar to the motion offense the Spurs use today in that players aren't asked to move to pre-set spots on the floor like robots, independent of what the defense does to counter. Instead, their movements are all reactionary to what the defense gives, with counters built in to every variable. In theory, any of the five players has the same chance of getting an open shot, so one can imagine Michael Jordan's chagrin when Jackson, the rookie coach, first pitched it to him. In fact, according to Sam Smith's superb "The Jordan Rules," Jackson told Jordan during their initial face-to-face meeting that he didn't want him to lead the league in scoring any more.
To no one's surprise, Jordan brushed that "suggestion," aside and continued to rack up the shots and the points, pacing the league in scoring all seven full seasons he played for Jackson. The coach just had to accept that the statistical distinction was important to Jordan. Chicago's superstar at least did it through the confines of the offense for the most part, breaking the play mostly to bail the team out at the end of a shot-clock or in late-game situations when he needed to play the hero. It's likely that the most "pure" form of the offense the team ever ran was in 1993-94, when Jordan was off playing baseball.
Jackson took Winter with him to Los Angeles, and again the two of them were successful until Winter retired in 2008. There's no doubt that the Triangle was tweaked somewhat to incorporate the high number of post-ups that Shaquille O'Neal's presence demanded. They ran the offense through him in the low post to a large degree, with O'Neal finding shooters when doubled. Kobe Bryant, of course, was the release valve in expiring shot-clock/late game situations, but like Jordan before him he frequently sabotaged plays to get his shots -- but to a more perverse degree, to Jackson's constant irritation. The Lakers also ran plenty of pick-and-rolls for Bryant and Shaq, and straight up isolations for Bryant.
It's difficult to say whether the Triangle offense had anything to do with the Bulls and Lakers' success or if Jackson benefited by getting to coach Jordan and Pippen -- and then Shaq and Kobe -- in their respective primes. None of his assistants who got gigs of their own had any success at all when installing the offense on their teams. Either the players weren't patient enough to understand its concepts or maybe the coaches themselves just didn't install it properly, or perhaps it's all a bunch of hocus, entirely dependent on transcendent talent to make it work. Jeff Van Gundy was certainly skeptical of it, mockingly referring to Jackson as "Big Chief Triangle," poking fun at Jackson's well-documented counseling methods borrowed from Native-American cultures. Perhaps it's telling that Kerr has declared that the offense he's planning on running with the Warriors will be a lot more similar to Pop's than Jackson's (though to be fair Popovich freely admits that he stole many of the concepts in the current iteration of the Spurs offense from the Mike D'Antoni Suns where Kerr was the GM for a time).
This isn't to suggest that we should dismiss Jackson's influence and not give him any credit at all. He was the first to install an offense basically without a traditional point guard running the show. Rather, he used his wings to initiate, while the point guards were little more than spot-up shooters. He also trusted fellows like Horace Grant, and later Dennis Rodman, to initiate from the high post, acting as both passers and screeners simultaneously. Jackson was unafraid to let his guards post up (both Jordan and Bryant had massive success at this) and he fielded ferocious defenses despite employing big men who weren't imposing shot blockers. Jackson's Bulls teams made their bones on defense, using the length and athleticism of Jordan, Pippen and Grant (later Rodman) to devastating effect, foreshadowing what Erik Spoelstra would accomplish in Miami a generation later with his three excellent defenders. Sometimes Jackson used the 6-foot-8 Rodman as center with Toni Kukoc as a stretch four, causing mismatches all over the floor.
Jackson also introduced the concept of ignoring traditional timeout situations, refusing to "bail out," his teams when opponents were making runs at them. He left his guys on the floor to figure their way out of jams. It taught his players to trust one another, to not panic when adversity hits, and to learn communication and problem-solving skills. Pop would borrow from this idea to a degree. He often calls timeouts and doesn't say much of anything to his players at all, relying on his veterans to communicate to the younger players what is going wrong on the floor and how it can be fixed.
Jackson's Lakers teams often won with offense more than defense, bludgeoning people with O'Neal and then unleashing a hail of threes from everyone else. He had Robert Horry as the stretch four and the Lakers were basically unguardable when O'Neal was in shape. Jackson was the first coach O'Neal truly respected in the pros, with his cache of six championship rings. He got O'Neal to play out of his mind for a couple of seasons. But it didn't last. After 2001, O'Neal ballooned up, preferred to play his way into shape from training camp on, stopped trying on defense and took plenty of regular season games off mentally. All of this only caused Bryant to have more free reign and Jackson spent most of his time playing traffic cop between the two. Things got a lot more comfortable for everyone once O'Neal moved on to Miami and the team had only one clear "alpha dog," to manage, with everyone else settling into their roles.
Pop is renowned for his "system," and J. Gomez wrote a fantastic column about it late last season. The Spurs offense was designed collaboratively with the efforts of Mike Budenholzer, Brent Brown and Hank Egan, Pop's old coach at the Air Force Academy. But the current version bears little resemblance to what it was in the late 90s. In truth, contrary to popular wisdom, the offense had more interesting wrinkles during the Spurs first title run in 1999 than it did when Parker and Ginobili first showed up. Back in '99 when David Robinson was still spry, the Spurs ran some funky hi-lo stuff between The Admiral and a young Tim Duncan and occasionally incorporated Will Purdue in a "three towers," attack. It was at least different. Once Robinson's back started betraying him and he became less and less of a factor on offense, the Spurs became more and more dependent on Duncan, resorting to straight vanilla post-ups in a 1-4 set, similar to the ugly stuff Houston and New York were running with Hakeem Olajuwon and Patrick Ewing in the 90s. They threw it into Duncan and surrounded him with shooters and the system was rigid, not ready to employ the burgeoning talents of Tony Parker or Manu Ginobili at first.
By 2005 the offense started evolving, becoming more guard-oriented, with pick-and-rolls and high screens for Ginobili and Parker and inverted pick-and-pops for Duncan. Really from that season on the Spurs never ran a "boring" offense, but reputations die hard among the mainstream media. Pop and his staff constantly continued to tweak and innovate based on the talent at hand and the league's rule changes regarding hand checks and the relaxing of illegal defense rules. They were constantly ahead of their time, figuring out the value of corner threes before anyone else caught on, rejecting mid-range shots as much as possible and emphasizing the concept of passing up good looks for great looks.
The last few years, after the Suns handed them an embarrassing playoff pasting in 2010, Pop embraced playing with pace where before the Spurs liked to grind the clock down as much as possible. They figured out they were undoing the efficiency of their offense by limiting possessions when the math told them the more possessions they could get, the better. It took a while to get to ball movement nirvana -- although they came close in the second half of 2012 -- but finally by 2014 the Spurs had built a roster of capable passers where every man on the floor was a threat to score and all were unselfish and had played with each other enough to have the minimum amount "corporate knowledge." Pop's system grew so refined that the Spurs could be competitive in games even when their Big Three were resting.
But Pop's true genius has always been on the defensive end. He had massive success overloading the strong side of the floor way before Tom Thibodeau did it as the defensive coordinator of the 2008 Celtics and later the skipper of the Bulls. Pop's defenses are predicated on always shading toward help to protect the rim first and foremost while fouling as little as possible to make opponents earn their points from the field. The Spurs are among the league leaders in fewest fouls year after year.
The tenets of the defense also include denying open threes whenever possible, especially from the corners, while encouraging opponents to take long twos. They don't really double-team stars, especially on the perimeter, preferring to let them fire away on contested jumpers. Pop's biggest point of emphasis without fail is getting back in transition, and again he was ahead of his time in figuring out that offensive rebounds are highly overrated, and very often not worth the gamble. The consistent themes for why the Spurs have been among the league's best every season in the Duncan/Popovich Era is that they've protected the rim, rebounded well in their own end, not fouled much while preventing too many fast-break points. It sounds simple, but you'd be surprised how difficult it is to get teams to do those four things in the upper quadrant of the league for even one season, let alone 20 of them.
In conclusion, I'd say Pop gets the slightest of nods. He hunkered down in one of the league's smallest markets, and built an empire that extends forever outward, with tentacles across the globe. The Spurs continue to produce front office material for other teams as well as coaches. Popovich hired Buford -- and together the two of them produced a host of general managers. Dell Demps (Pelicans), Danny Ferry (Cavs/Hawks), Rob Hennigan (Magic), Dennis Lindsey (Jazz), Sam Presti (Thunder) and Kevin Pritchard (Blazers/Pacers) all rose from the ranks to lead franchises of their own. Buford joked to the press that the reason he finally won his first Executive of the Year Award in 2014 was because he finally had enough proteges to stuff the ballot box in his favor. The Spurs continue to push new boundaries, hiring well-regarded European coach Ettore Messina as an assistant for the upcoming season as well as Becky Hammon, the first female to be a full-time assistant coach in the league.
In terms of just coaching, he's done more with less, especially the last two seasons, and has been more consistent and innovative on both ends of the floor and beyond. He's more of a pure coach whereas Jackson could be described as a relentless self-promoter and a manager of demigods. That's not to say that Popovich didn't have tremendous talent too, but what he's pulled off the last couple of seasons with a diminished Duncan and Ginobili is truly extraordinary. I don't know how anyone can argue that he isn't the best coach in NBA history.