I'll phrase it this way:
To UConn fans: Drummond has something to prove.
To NBA scouts: Drummond has (almost) nothing to prove.
And I'll kindly bow out of this conversation here. Commence trolling, trolls.
Yeah, he has nothing to prove if he wants to get drafted in the top ten. That doesn't mean it is in his best interests to leave now. Scouts see in Drummond what everybody else can see in him. You're looking at this situation from a very narrow perspective, one in which the only possible correct move to make is to go pro right now. Consider the pros and cons of declaring for the draft right now:
Benefits of going pro:
-Immediate money, set for life
-Chance to get better every day against some of the best basketball players in the world, while collecting a lofty pay check.
-Opportunities to work with some of the best trainers, coaches, and teammates in the world.
Benefits of returning to school:
-He gets another year to grow into a man through Big East competition and Jim Calhoun coaching--a kid who is willing to bang bodies in the Big East will have no problem doing it in the NBA
-He stays at a level closer to where he is as a player right now, eliminating the risk of entering the draft and overwhelming himself.
-Has the opportunity to develop not just his physical skills, but also his intangibles (I.E. the ability to dominate a game)--if you're ever going to dominate in the NBA you better first learn to dominate inferior athletes
-One on one coaching from one of the best teachers at any level in Jim Calhoun
-Better understanding of how to play the game (I.E. how to post up, how to play help side defense, how to screen, back to the basket moves, defensive rotations, passing out of the post, etc. etc.). These are all skills that ideally, a player should know before entering the draft.
-Prepares himself (in my opinion) for a long, successful career rather than a shorter, more limited one.