Calipari recruited players based on NBA potential, not size of their college contributions. Other coaches weighed college contributions more, and were OK with having a great college player for four years who was of little interest to the NBA. Calipari sought guys who might be good but immature in college for one year and then go to the NBA, drafted on potential; then he used draft success of his players as a pitch for the next recruit.
Calipari has a good eye for talent, that's for sure, but whether he's a good developer of talent is open to question. He seems to be an average developer, based on an analysis I did a few years ago. Not bad, but not like Jim Calhoun in frequently lifting players above their high school recruiting rankings. For every Devin Booker who overperformed, there was a highly touted recruit who underperformed, and vice versa.