Sometime after Syracuse head coach Jim Boeheim adopted the 2-3 zone as his full-time defensive scheme in the mid-1990s, a belief was born that playing the zone damages players' NBA potential.
The theory is that since man-to-man is the NBA's most frequently played defense, Boeheim's zone doesn't properly prepare its players for the league. Supporting the theory is the idea that Syracuse players aren't successful in the NBA, which isn't necessarily untrue. But it's not because of the 2-3 zone.
Let's start with this: in terms of being a hotbed for talent, Syracuse isn't Kentucky.