the US miners will not be happy when they cannot include the most lucrative transactions in their blocks. Eventually if this economic incentive gets strong enough the hashpower will simply relocate out of the US

This is what I've been concerned about for over a year.

I don't actually think the conclusion of this scenario is mandatory OFAC blocks. the state doesn't have to make the miners do anything in particular. I actually think that in a mass adoption scenario, bitcoin will never shake off its inability to scale without custodians, most people will be stuck on some kind of custodian, and the most visible custodians who legally do business in the united states will have KYC. a small number of people around the world will be able to afford to own their own UTXOs or channels and their money won't be accepted by the compliant custodial services. you'd be able to buy a hard drive on newegg using the money you have in strike, but not the money you have in pirate jim's ecash mint. you end up with two sets of coins that realistically will diverge in price.