Via JD's UCLA Basketball Blog, I came across an online version of a New York Times article from 40 years ago reporting on Lew Alcindor's announcement of his choice to attend UCLA (Alcindor, of course, later changed his name to Kareem Abdul-Jabbar).
Although the Bruins had already won two NCAA titles (1964 and 1965) before Alcindor's arrival, his impact still played an incalculable role in propelling the UCLA dynasty further upward (remember also that he could not play varsity ball at UCLA until his sophomore year, 1967, under the rules of those days).
In fact, it's probably a reasonable conjecture to say that, absent Alcindor at UCLA, the Game of the Century might never have taken place. Without him, a UCLA-Houston match-up could not have pitted the two big men, Alcindor and UH's Elvin Hayes, against each other. Perhaps there could have been a game between Houston and whatever other school Alcindor (hypothetically) would have gone to, but that probably would have required the "other school" to win the 1967 NCAA championship (which UCLA did), to lay the groundwork for a Game of the Century in 1968.