Correct me if I wrong, but I think rookie contracts in the NFL are 4 years guaranteed. And if it were up to the owners rookie contracts would likely only be 3 years. And it might end up there as spillover effect from the NIL era of college.
I think in the next 5 years playing in the NFL or playing football anywhere is not going to be as lucrative as it has been unless you can make 7-8 years in the league. There will be an even a further move toward talent cycling in college and the NFL but the USFL will benefit from this as well.
How interesting would it be, if allowed, for NFL washout to actually come back to college to play for the scholarship and the opportunity at a real education? Sort of like the opportunities that MLB offers their minor players only that you could opt for amateur status except in the same sport you were a professional. And what NCAA rule, that is enforceable, would prohibit this?
I mean, JUCO doesn't account against eligibility now. Just make it a free for all for recruiting players whether they are HS graduates, transfers from other programs, NFL washouts, JUCOs, international players, former minor league baseball players. Heck, I would hold tryouts like the Philadelphia Eagles did way back to find players. Give them 5 years to play 5 years.
Essentially, if you play sports now, you are deemed a professional unless you elect to be an amateur, under the argument no one does anything for free unless they choose to do so of their own free will.