If students already pay a hefty athletic fee, then their seats are not gratis. It's a different story if those seats earn more general public revenue. So, with that, let's call a spade a spade: Most students now are not into the "old college game," if they ever were. They're at school to learn and earn a degree to pursue their personal goals. Many, if not most, work jobs, have families, etc., in addition.
Make the athletic fee optional: No fee, or selected sports. Officials should be able to gauge that to predict possible student attendance, and provide seats for the paying public. If a student declines the athletic fee altogether, he/she should pay to attend as a general public.
But, let's get real, here: For several decades, now, UM games have been chiefly supported by alumni and community fans. It hasn't been about the students for ages. As I say, let's call a spade a spade.