but I also said that Cheeks and DiLeo were bad coaches who didn't know how to develop players
Sam's lack of development has been in place LONG before Cheeks and DiLeo
At what point does a players lack of development in the basic fundamentals become THEIR fault?
IMO, the Sixers have not had a good coach since L. Brown, and Larry is notoriously slow to give Rookies a chance to even play. I'd say that it was always Sam's fault that he hasn't learned fundamentals, if you get a contract to play in the NBA, it's your responsibility to work on your game and find help, even if your team doesn't get it to you.
Sam should be dribbling the ball everyday. Get some people to pass to and receive passes from, Copying premier players post-up moves until they are automatic and he can do them blindfolded from specific spots on the floor. He should have been doing this from the day he was drafted!
It's obvious watching him play that he's a bit of a spaz and doesn't understand the game, which implies that he has a limited upside as an offensive player. At the same time he is and has been a good shot-blocker and rebounder when he has been able to stay on the floor and out of foul trouble. However, no player can be expected to give his maximum effort when no plays are run for him and no-one passes him the ball with any regularity!
A player who isn't challenged and asked to develop usually doesn't. Not unless they have a strong work ethic and a burning desire to succeed. Sam isn't proactive and probably has few people in his circle that he can trust. It helps to have someone with an objective view to tell you what you need to work on and what you are doing wrong. I don't know if he has ever had that. Even after being in the NBA for as long as he has, his comments suggest that he doesn't have a realistic view of himself or his abilities. It's hard to get better when you don't realize your weaknesses and some personalities don't take criticism very well.
It is his fault no matter what, but the Sixers clearly could have done more to develop him than they have.