The point isn't that anybody plays 40 minutes, but if you adjust stats over 40 minutes and for pace, then you can tell roughly how productive a player would be in a neutral system, relative to other players. That's the stat.
Well, it ignores other issues. Like what good is it to know how someone woudl do over 40 minutes if they commit too many fouls to play even 30?
Casey Mitchell was a very productive player on an overachieving basketball team. That's what the stat proves. Furthermore, if you notice that he shot well below 50% from 2FG, then you know that he was hardly efficient. Thus, what is revealed is that yes, Casey Mitchell was absurdly productive on a slow paced team in limited minutes. The reasons for that are not explained by the stat, but the stat does say that he would have gone nuts playing for VMI. Not sure what your point is, though.
I'm gonna go ahead and guess that I saw more of Casey Mitchell's career than you did. He was a maddening player, and not just to me. I imagine he drove Huggins to drink even more than he already did. He scored a lot of points, but not always (or even often) efficiently, and other aspects of his game were mediocre. His effort wasn't always the best. And that's why he didn't play 30 mpg and why his per 40 production is a pointless number, because he was never going to manage to stay in the game long enough to even get close.
I think Thomas Robinson is better than Jared Sullinger right now.
And we're done here. I've already had a crappy day, no point making it worse trying to argue with someone that would seriously say this. Perhaps you're not serious. FYI, the issue with fouls and minutes and rebounding is striking a balance between aggressiveness and needing to stay on the floor. When you're a backup if you get 4 fouls in 15 minutes, it's not as big a deal.