What are the consequences to the Texans? If he holds out, they have no decent QB and they can't just go out and sign a big name QB because Watson could always change his mind, show up, and blow up their cap. The only way it makes sense is if they are tanking on purpose.
If you are trying to be an NFL team, it's hard to sit on him just to stick to your guns. It makes so much sense to sell to the highest bidder if there is 100% no chance of him signing back.
On the flip side the new GM can come in, use it as a rebuilding year (they're fucked anyway, are in cap hell, and have no first round draft) and completely just tank fixing all their cap problems and almost guaranteed at getting the 1st overall pick the following year.
The terribleness of the entirety can be blamed on the previous administration, and suddenly you have a team poised to make a fairly substantial turn around.
And its not like they can't easily just decide to trade him the following year.
Honestly if I were a Texans fan I think unless you get a mountain of gold for Watson, the preferred option would be to just let him stew and embrace the tank.