Similarly with potential wives. They could sign contracts that agree they will never sign prenups--another hawk/dove equilibrium.

I'm baffled by this logic. If the two people want to be together, but have incompatible contracts, then they still get to be together. They just won't marry. This is still a total win for the pro-prenup-contractor, who doesn't risk losing any money. But it's a loss for the anti-prenup contractor, since they don't get to gain any money.

In contrast, the person without an anti-prenup contract gets to be married, but can't get their hands on the pro-prenup contractor's money.

Which of these two sounds more socially acceptable? And which is more likely to seem desirable to the type of person the pro-prenup contractor would prefer to marry in the first place?