I do not think relegation can be added to football without contracts/trading/transfer restrictions. I doubt even soccer would be able to sustain all players having single year contracts where they could just leave instead of having to fulfil contracts.
I, for one, think that expecting student athletes to fulfill their commitments to play for a school is an important life lesson.
I committed to Tech (as a student), and I hung in there for five years when transferring to NC State or Carolina might have been an easier way to a degree. There's a REASON why Tech alumni do not ask, "When did you graduate?" We ask, "When did you get out?" But I digress.
I might concede one exception: if the Head Coach of the team leaves for any reason. One other variation: an athlete can transfer ONE TIME after TWO SEASONS. Okay, one more variation: if the school mutually agrees that the player isn't working out, they can release him.
Other than that, you dance with the one that brung ya.