I don't see why it couldn't end up that way. Players and agents stand to make much more money if contracts are shorter, they run them down, and then take bids from interested clubs for signing bonuses and wage packets, etc.
Clubs might still make some money, or recoup some cost, if things aren't working out and the deal is longer than anyone would've liked. "Sales" will still happen, but I don't see why players and agents would want to be letting clubs take such a huge cut of their transfer deals.
Player sales aren't exactly the bread and butter of PL clubs anymore either. There's no real reason to sign a long contract unless the money is ridiculously good and you know you don't want to move, but even then, you lose so much leverage.
