I don't agree for a minute that everyone should compare their last year in the NBA to their next year in college, because their last year in the NBA can be a very different story depending on whether they get a foothold in the NBA during their first two years. Also, the salary along the way can impact that decision and should not be disregarded.
There are dozens of players that wash out after their rookie contract because they can't get over the hump to earn significant playing time and that inhibits their development. If a player will set themselves up for meaningful playing time with another year in college by moving up 10 spots in the draft (in fact, even if they drafted at the same spot), then it can pay off way more over the long term. I'm not saying it necessarily will, but that's what Demin needs to figure out.