If schools pay high end players with endorsement money or even a share of revenue do you think they have thought about how that impacts the NFL. Specifically the motivation to make the money for the work needed. If you were in college and can make a couple million would you be motivated to work your ass off at the next level. Some will hang it up and be content with their earnings. Some will have residuals from endorsements and can retire. It may make a mud hole like the shoe contracts in basketball. Manhattan can't "endorse" players like LA or even Lincoln where a whole state can pour money on players.