If "they" killed the internet or power grid, the consequences would be Ragnarok.

The world would become even more chaotic. This chaos would make it hard for "them" to continue to live in the ways they prefer for any number of reasons from hit men to supply line disruptions.

Aren't there ways to broadcast Bitcoin txns using radio? I'm pretty sure someone was doing that at least 5 years ago.

Lastly, if we are willing to bootstrap our own monetary network and our own social media protocol, what is stopping us from bootstrapping our own mesh grid network and setting up our own local renewable energy grids?

We're kind of already doing that with the decentralized mining farms.