I want to point out the survivorship bias present here too. Only buried cities can survive millennia to be discovered later. Abandoned cities that were in erosi

I want to point out the survivorship bias present here too. Only buried cities can survive millennia to be discovered later. Abandoned cities that were in erosion prone places are in little bits at the bottom of the slope. Cities that weren't abandoned can have buildings that are thousands of years old and actively lived in and maintained. I spent some time in an Italian hill town that has been continuously inhabited since the Romans. At the same time I visited Pompeii. Most of the buildings in the center were Roman and had identical construction to Pompeii. They were living "ruins" and therefore could not be discovered because they had never been lost. There was a Roman Theater in that town that had been partially built into homes and partially quarried for building materials. There had been a set of giant marble masks originally in the theater, but now scattered around the town built into other building. Conservation of matter, it doesn't go anywhere unless someone carries it away.