What do you mean by govs can do a 51% attack? You mean call up the big pool providers and order them to act malicious?

Every miner part of the gov pool could instantly switch in that situation.

I think Bitcoin's resistance to 51% attacks is extremely solid.

Most important are economics of scale that you have to actually acquire physical Asics and can not start your attack from AWS or something similar.

There is also a protection from the physical space where you can only put X amount of asics in your warehouse and not endlessly scale like in the shitcoinworld of "Proof of stake".

From an incentive standpoint you would create a lot of dead capital if you successfully managed to destroy Bitcoin. The incentives are not aligned for you to spend trillions on buying machines just to throw them away the next day since asics can not be used for anything different. It is more profitable to try finding blocks with that hardware than go for the attack.