People will say Houston has the leverage because they hold the contract, but if he's truly done with them, the longer they wait, the more his trade value goes down.
This isn't a Le'Veon Bell situation where there's one year of control left. There's no upside to the team trying to call his bluff if he's truly willing to sit out. The closer they get to that point, the less trade value Watson has, because teams will know the Texans are desperate and without options.
Not only that, but also, teams aren't going to wait forever to resolve their own quarterback situations. The more teams that bow out of the Watson sweepstakes, the worse it is for the Texans. They want a lot of teams jumping over each other, and the only real way to do that is to trade Watson on draft night. ***Remember that you can only trade three years into the future, except on draft night, when you can add another pick.***