I always tell my gun-hoarding, go-box toting, bug-out planning prepper friends the same thing. You don't have enough guns and ammo to stop the masses coming for your canned pork'n'beans.
I guess an army of thousands could take it over but my hope is that me and my gun toting farming community won't put up with invaders and invaders won't want to take their chances
I quote "equilibrium" because social structures never stop changing. What I mean is a relatively stable situation where most of the world is not invading the rest of the world. Our present situation is that the larger portion of the population is not invading the rest, though the present trend seems to be in the wrong direction.