No one gets a four-year scholarship, they're always just a single year that renews each season. A coach (think Saban) can decide to simply not renew a scholarship and tell that to the player and then the player has to decide what to do. There's also the deal where a school (think Alabama) has offered some high school kid, kid has committed and stayed true throughout the whole process, and the day before NSD someone else the school wants more decides to flip and come there, so the committed kid who stayed true to his word and didn't take all those other visits is now left hanging without a scholarship. To help get rid of the first situation, they should let the school have more than 85 kids on scholarship but for those over the 85 limit they can't participate in football at that school ever again (if they stay they still get a full ride but their playing days at the school are over). For the later NSD case, they should let kids and universities sign the letter of intent whenever they want to during the kids senior year. There's no NSD, once you and the university are ready to commit, sign it and you're set.