I DO NOT practice in this area at all, so I'm not claiming expertise. And I think it would be a loooong way off, and a difficult decision politically. But you aren't a nonprofit just because you don't profit. You still need to fit into one of the enumerated purposes and not do stuff that isn't allowed.
I also think it becomes harder for nonprofit universities to claim that they don't at least have unrelated business income as athletics continue to become professional? "Income from a trade or business, regularly carried on, that is not substantially related to the charitable, educational, or other purpose that is the basis of the organization's exemption." So they could at least be taxed on all of the athletic profits, including broadcasting, concessions.... They've avoided that to date because it's done to support amateur athletics which is a purpose of their exemption.
Then again, most athletic departments run at a loss, so maybe it wouldn't impact them anyway! Or maybe it will cause a resurgence in non-revenue sports to act as tax deductions? That's what I was referring to when I said I was interested in the other stuff.