No, they can’t. And even if they could the network would just fork to a different hashing algorithm, which means that the attacker would have had burnt hundreds, if not thosaunds, of millions for nothing.

Never underestimate what a government can do. If they want, they can make bitcoin as popular to hold as child p//n on your PC. Go ahead then

China can take console of all of their miners in the country which would all for a 51% attack to be profitable ignoring opportunity costs.

In this case forking does not help as they maintain control of the equipment and have access to massive CPU and GPU resources to swap to alternative architectures.

Now, if you think bitcoin maintains value if there are zero transactions for ~6+ months you are clearly mistaken.