I also think that football should have a minor leagues. There are so many good football players, and some of them who are not ready at 22 might be superstars at 25. Happens in other sports all the time. But in football, the ones who don’t make a team at 22 are pretty much done. Some hang on, but without actually playing it’s hard to get better. Look at Kurt Warner and how easily he might never have actually played a down.
The NFL does have a Minor League, its called the Canadian Football League.