If you want to be reductionist, you can argue that since almost all of the world's land, people, resources, and equipment are under the control of some government, it's hard for anything to be independent of them.

I don't think that's reductionist. I think that's a reasonable statement. It is indeed hard for anything to be independent of government control, except perhaps in failed states. Which is sort-of the definition of a failed state.

Well, yeah. Why else would Elon want a Mars colony so badly?

If electricity became less available the mining rate of Bitcoin would automatically adjust to the scarcity of available computation - it's not like there's a specified amount of electricity that has to be used per transaction.

It's less about steady-state global availability than burst capacity. What if the People's Liberation Army decides that temporary control of the Bitcoin network is a valuable capability?