There's a ton of downside to this, I know, but I don't think that universities should be regulating what sort of money their students bring in.
Another way to look at it is that the university is 'paying' them with a free education, and 4 years with no financial obligations. Depending on the school, that has the potential for massive financial equivalents.
That said, let me propose a deal for you: Instead of being paid for your next four years of work, your employer gives the cash to a university. In return, the university gives you a four-year scholarship with a value equal to your deferred salary plus X%. Note that the scholarship is nontransferable, it cannot be deferred, and you cannot stretch it out over more than four years, unless the university agrees to give you a single extra "red-shirt" year. Also, if you quit your job, you lose the scholarship, so don't expect to be a full-time student unless you're really good at multitasking and don't need a lot of sleep.
How large does X have to be before you accept this offer? My guess is that it is considerably higher than zero.
If I were a high-school kid coming from a family with very little ability to help pay for college I'd say that sounds like fantastic deal.
Some of these guys come from financially destitute situations and will leave school the minute they hear NFL so they can support the rest of their family.