Then we would know. And we might not like the results. He would still score a lot, but likely not as much, maybe 20-25 ppg.
If a team builds their offense around him, then one of the problems would be what to do if he is injured. The offense is built around him and there would be no one else that could step in and play the way that he does.
Even if Jimmer could average 30+ ppg. It still wouldn't be a sure thing that his team would even make it to the play-offs. He would need good players around him and that would mean he needs to get them involved in the offense more, so less scoring for him.
I would love to see it happen but understand why NBA teams don't want to take that chance with him.