To compare those who skipped college all together with those who played college ball and then went into the NBA is a spurious argument. I don't think any players development as a player is hurt by going to college - maybe their hype is just lessended.
Not to long ago to even entertain the though of going from HS to the NBA you were a world beater, now it seems you just have to be very good and I think alot of those who jumped directly will wash out of the league who had they played some (or more) college ball would have been better equipped .
There are only so many NBA spots and it seems to me alot of young players throw themselves into the draft who should not. I remember how Caron seemed just OK until the light went off and he became unstoppable his last year - I think progressively playing better talent allowed that. Had he left college b/ would he have had the confidence he had as a result of playing in college with good, but not NBA caliber players?