> protect yourself from the roving looters and/or warlords that will immediately spring up in the absence of law and order.

This is a hollywood meme.

The reality is that aggressive looters/warlords will be very quickly disposed of and the remaining ones will fall in line and become semi-official protective militia forces, who will labor alongside farmers in small communities if they don't want to starve.

Food scarcity will be a much bigger issue that some nutcase trying to loot my solar panels.