The NFL ought to have a developmental league similar to what the NBA has - each NFL team having one team in it, of which they retain the rights for maybe half the players. There is plenty of talent around considering all the college players graduating each year. Pay them very little; Let ticket prices and fan interest mostly sustain the cost.
This shouldn't be that hard to do. Some of us remember the player strike a couple decades ago when the NFL teams threw together scab teams almost over night, and while way short of NFL quality, they didn't embarrass themselves either.
You could really draft and develop with that with a lot less reduction of quality on the major league level. I'm pretty sure fans would support it. I see no real down side to something like this.