That is an important point. If players or sponsors start competing for donor funds directly to NIL pools, then the University's interest in the endeavor becomes questionable. Right now it certainly seems like the least likely outcome, but you can at least envision an evolution of more or less minor league effectively at arm's reach from the U that plays in the University stadium Saturday while the university has a non-scholarship student team playing other schools there on Friday nights.....
In the current system, a school like UM clears enough after expenses to use revenue sports income for non-revenue sports and student recreation facilities, plus whatever cachet the football program adds to general donations, which they probably have some idea about. If whatever new system evolves does't result in at least that much revenue to the institution, it will be a problem.