The problem right now is that players, especially men's basketball players are being babied, told that they're on top of the world from high school (and AAU especially) through the pros.
These one and done players overall are mostly divas to some degree and being babied makes them less coachable. Even John Wall isn't exempt from this either as there was a story about John Wall requesting his coaches to fine him every time he pouts and does something potentially detrimental to the team during games, practice and otherwise. Sure, John wants to correct this stuff, but I don't think the NBA is the place for players to learn how to be professionals either.