Early in Wilt's career his teammates just passed him the ball and watched him put up points. At this point Wilt is kind of like a side show act where they would pay money to cheer against the giant monster scoring 50 on their team, but this was more of an individual showcase than a team first approach. He was kind of annoying behind the scenes as one of his favorite moves is to threaten to retire unless they pay him more money, he did this many times including after his rookie season. He finds a coach who is the Wilt whisperer in Alex Hannum, who gets him to pass more, etc. leading to his best version yet in 64. The next year, the chemistry between Wilt and teammates collapses again, the Warriors don't want to meet his demands for more money, so he gets traded to 76ers. The 76ers actually have a talented team with young players like Hal Greer, Chet Walker, Billy Cunningham, etc., meanwhile the Celtics while still having several other stars their talent advantage is not like it was in late 50s and early 60s. Wilt no longer has a talent deficit compared to Russell. In 67, they hire Hannum and once again he unlocks Wilt's passing game and they have one of the best seasons ever and beat the Celtics. End of the dynasty now it's Wilt's time? But in 68, Wilt becomes stat driven and tries to lead the league in assists. They have some injuries in the playoffs and MLK murder is a distraction and they blow 3-1 lead to Celtics. Maybe not his fault. Wilt then asks for a trade to LA for a variety of reasons, some of it the same reason modern players want to go to LA, Hannum retired, maybe thinking he needed West and Baylor to beat the Celtics. So he goes there and the early results are kind of underwhelming. Wilt was used to playing in high post passing game in 76ers and they weren't really sure how to make it work in LA, if anything they wanted him to be more aggressive scoring. They still put it together enough to make it to G7 of the finals but lose to the Celtics again with West playing great but Wilt not coming through. Overall even after the 76ers trade to balance the talent the Celtics win 4 of 5 titles against Wilt (65, 66, 68, 69). The Lakers go on to face the Knicks the next year and after a great game 6 Wilt gets defended by one legged Willis Reed as they lose in 7. Throughout his career Wilt is known as kind of a playoff letdown, some of his playoff games he only puts up stats in garbage time. The Celtics have some of the most clutch playoff players of all time like Russell and Jones. This is part of though not all the reasons they managed to pull through time and time again over Wilt. Wilt eventually wins the title in 72 with another all time great team, but he does it taking less shots and playing defense and scoring efficiently - Kind of a Russell impersonation.
Overall while Wilt is a great talent he has a mixed results in terms of chemistry with opponents, playoff clutch play, stability by asking out or for more money so much, and prioritizing different parts of his game at different times - early on he's scoring too much instead of passing, later on he's trying to pass too much instead of scoring, it seems like he didn't quite have the instinct of when to use it at the right time. In modern day we've seen the impact of players who didn't quite get it, with the Hardens quitting on teams repeatedly, Durant albeit piggybacking for 2 titles on Warriors having other teams that self destructed, etc. meanwhile a guy like Duncan has 5 titles by being consummate teammate. Thus Wilt being the daddy of this modern player like Harden and Durant should be taken seriously when evaluating him.
Russell has tremendous intangibles and commitment to winning, always trying to make his teammates better, and is known in the playoffs for always coming up with the big play at the right time. However, if you watch him based on the limited footage we have, it doesn't look that awesome. Reportedly, he barely even blocks more shots than Wilt. In general, I'm confused by how ridiculously successful the Celtics are. Yes they have a great roster, but it's a condensed league where other teams also very good, as mentioned the 76ers in the late 60s, the Lakers had West, Baylor and other good players. The Celtics had some guys retire like Cousy and Heinsohn and there was no transition period where they stopped winning titles. The Celtics in the 70s had another great, underrated center in Dave Cowens and his core of older John Havlicek and Jo Jo white is not that much worse than Havlicek and Jones, and some other players like Paul Silas and Paul Westphal, and they got to play weaker expansion competition (ie they didn't have to beat anyone in 76 title), but they still weren't close to as dominant, with a comparatively normal 2 title team. So why were the Celtics that good? They are by far and away the most dominant dynasty in the major sports, the 8peat blows away any Yankees, Canadiens, etc. team before getting to the 3 more after. It's hard to come up with an explanation other than Russell being that dominant. Maybe he was quietly impactful on offense to go along with his D impact, I don't know.