RealGM

In this hypothetical scenario.

Phill coaches Russell from 1957 to 1966

Red or Phil coaches Magic from 1980 to 1989.

Red coaches Jordan from 1990 to 1998

Red or Phil coaches Wilt from 1960 to 1969

Red or Phil coaches Bird from 1980 to 1989

Red or Phil coaches Kareem from 1970 to 1979.


Which one of the two do you think would achieve the most team success with each of the players I have listed?

As Russell had the most team success anyway and I think Phil is a better game coach and tactician than Red (at least if each have their accustomed assistants like Tex Winter), Russell's Celtics still win the most.

Now, the biggest differential from actual results is another story. Wilt and Kareem are the two who can be said to have underperformed their expected team results so they would be the two candidates. Of them, Wilt came the closest to success multiple times in the Sixties and possibly with a GOAT coaching candidate he'd break through in some of those elimination games that the Celtics always won. It's far from certain but it's the most probably improvement. Kareem might win another title early and another one or two before he broke through with Magic as well though so that's the other possibility.