If this scenario happens, BTC will have demonstrated enormous power and value, and it is supposedly designed precisely to resist such attacks.
I also doubt on the feasibility of a global crackdown on miners in the entire world.
The enormous value being money laundering? Also the miners ultimately have to swap for some fiat, so they can’t stay in BTC “heaven” forever. Further buyers set the price, not miners. Especially given that using BTC is a luxury except for the underbanked, who also don’t have money and are selling their BTC to get some.
And will quickly be banned by said country.