“they will generally last longer than those who build little supply depots.”
They will function on what logistics exactly? Fantasy guns-a-blazin doesn’t work in the real world. Inadequate logistics loses wars. Those supplies and logistics systems “preppers” have are the very supplies needed to win and survive any war.
Gee.
You haven’t looked at oil pumped out of the ground in your neck of the woods and at what is needed to set up a refinery to produce fuel to run ... not tanks or troop carriers but tractors and generators?
You haven’t been looking at arable land and calculating how much land could be returned to agriculture to feed people?
You haven’t been done the same work looking at the water supply, and at what can be done to keep your Aquafina from being tapped at other points?
Every one of these resources exists close to me, and I don’t live here by accident.
What about food distribution? If you are providing food you need not only enough security to guard it but enough security to identify bad actors and remove them in your distribution process.
Have you identified machinists, engineers, and chemists that you will need to make a functional economy?
These are not arcane or impossible tasks.
Nor are they things that are not being done.
All of them are more important than trying to build a little hole in the ground.
If you wish to try to live in a hole your best bet will be in urban centers. There is little agricultural use for them and logistically military forces would extract anything useful from them early on and bypass them thereafter. .