True, but even in that case the return would still theoretically be declining between now and then I'm not entirely sure that's true. You open the potential trading partners up to the whole league instead of just those who are pushing (ie, the Cubs aren't going to buy now, but would in the offseason), and you also increase the players that a team can afford to give up (ie, the Giants, who are unlikely to trade away a starting pitcher because they can't afford to open a hole in their starting rotation for their push, when that wouldn't be an issue in the offseason).