You regulate the fiat onroads.
If miners cannot sell their coins, they can't pay the electricity bills.
Bitcoin will always be around, but with sufficient fiat blockages the value plummets.
Governments should announce that people will have a year to sell all their coins (the price will tank immediately anyway), and then buying and selling of PoW coins will be banned.
If you think "lack of electricity" is going to stop bitcoin mining, you are mistaken. You are just hoping for doom on an asset you don't understand or don't like, it's just not a good way to argue against something.