I think he has a skill set that some people think should translate into "role player." They figure that if he can score 40pts against good college players and NBAD players, he should be able to put up 10pts/game in the NBA.

It doesn't work because he is not (and never was) a "shooter." He has always been a "scorer." To score the way he does, he needs minutes, and he needs to control the ball. There just aren't NBA teams who are going to give the ball to Jimmer for 50% of their possessions and see how it goes. He obviously isn't LeBron, or Kobe. Lebron and Kobe get to control a team that way, not Jimmer. If you squint and put on blue goggles, maybe you can imagine him in a Steve Nash, Steph Curry type-role. But (for the reasons you pointed out) he just isn't.