Well, you make a point — in the western US we have things called Ghost Towns where a gold or silver mine once produced a thriving town, but then the mine ran out. That’s in the dry desert where the things preserve better. I have traveled in the Pine Barrens of New Jersey and seen abandoned villages there — but little is left of them.
On another point the Goths were a peaceful society forced into war by the pressures of the Mongols and Huns.
What would the Taliban compare to? I can’t say. I draw a blank.
In the ancient past, pressure from famine, invading hordes (many someones outside of the society) force moves, changes and choas. Today - could it be ideology?