Overall, I think history has proven that there is no general rule (in terms of chance of success/$$) that applies to early entrants to the NBA draft -- it's really a player-by-player thing. There's a KG for every Koreleone and a Kobe for every Omar Cook. There are certainly valid reasons for a player to stay in school, but I don't think, for example, Lenny Cooke's professional prospects would necessarily have been better had he gone to college. Remember that teams draft more for potential than for immediate help now. It's almost like the less scouts know about you, the better. You can definitely expose a lot of weaknesses in four years of school. Watching Kwame Brown play last season, I wondered if he'd even be a dominant force in D-1 ball. But he was still the top pick. Is it bad for the game? Yes, of course. But is it bad for the players themselves? For the most part, I'd say no (with obvious exceptions like Zach Marbury or Victor Page, players who have nowhere near NBA-caliber talent). Even a player like Omar Cook still has a bright future. He had to spend a year in the NBDL, but he's in a great place now in Boston with their shaky PG situation. I always think that the cream eventually rises to the top.
No, there is not a KG for every Korleone and a Kobe for every Cook. The fact of the matter is that there are far more stories of failure regarding players that have left too early and only hurt themselves. KG, Kobe, and T-mac were special players that had the ability to make the jump. Some of the players that are taking the jump now are players that have NBA talent, but need to go to college to develop it. There doesn't have to be as many stories of failure as there is now, if these kids will just suck it up and go to/stay in school. Now if you're someone like Lebron James, who is being touted as the #1 pick of the 2003 draft, by all means, go. But if you're Lenny Cooke or DeAngelo Collins, and you're a second rounder at best, but have the talent to become a top 5, top 10 pick, where you can make the guaranteed millions that you desire when you decide to make the jump, SUCK IT UP and GO TO SCHOOL!