I’m not sure it’s true that nobody knows where they are. There are rankings by country. They need Internet access and power. Many operate openly. Large data centers aren’t invisible.

Also, miners were kicked out of Kyrgyzstan. Many machines were confiscated. It seems a lot of miners moved to the US because, even if they are eventually shut down, at least they will still have their machines, hopefully.

Governments could greatly reduce the hash rate by cracking down on miners who operate openly, and then Bitcoin would be considerably less secure against a takeover.

Suppose, after getting kicked out of many places, many miners move somewhere without strong property rights, and then the government takes control of the machines and runs them? Or maybe the miners keep running, but the government tells them which transactions to block?