> Everyone can generate electricity with solar panels or wind turbines, etc. Even if there wasn't a central government at all, bitcoin miners would still have resources to defend their operations.
If things deteriorate to the point where people were forced to self-sufficiently generate their own electricity, one of the last things they'd waste that power on is bitcoin mining.
Furthermore, you need semiconductors to run a bitcoin miner, which are so complicated to manufacture that, in the absence of a government, either manufacturing would stop or the manufacturer would become a government.