PoW miners face enormous costs and head aches in moving your PoW operation, not to mention the hardship of getting an industrial energy contract in the new country.
Takes weeks especially, if caught off guard about the ban.
PoS stakers can just move their laptop, or move their coins to a pool outside the country, at almost zero cost and within 2 hours all finished.
However if they wished, a PoS Staker can hide in any country and never be discovered since the energy efficiently hides them from all electric utilities.
PoW miners however, draw more power than residential use, and the electric utilities can pinpoint their location at a minute's notice.
A global pow ban with fantasy land effectiveness would cause the difficulty to drop to a level where laptops can mine if needed.
China did ban PoW mining. Fact
PoW Miners did leave China. Fact
There are still bitcoin miners in china.