collapse. Colleges, with all the rules and regulations they must follow (including Title IX), could never afford to pay the players. It can't and won't happen.
But don't kid yourself, as nobody's going to watch a "minor league." If you're an MLB fan, how many minor league teams can you name outside of maybe the feeder teams to your pro-team?
Name me any sport where there's any national interest in minor/developmental leagues? The money that college football generates is not going to simply transfer over to some minor league. College boosters lover their college team, not some random minor league team where the best players get snatched up mid-season. That money will disappear. The apparel money will disappear. The TV money will be gone (name me the last minor league baseball or NBA developmental game on TV).
The Clowney's of the football world will make out better. Like a Bryce Harper, they'll sign multi-million dollar contracts straight out of high school. The Daniel Sorensen's will suffer, as they will have to choose out of high school whether to risk several years making minimum wage chasing a dream with potentially nothing to show for it, or give up the dream and go to college. Won't be able to do both, as a minor league team is still a pro-team and will expect and demand all of your time.
I really don't know which system is better, as the current system is not fair to the athletes at all. But the alternative isn't exactly all roses, either.