Frank,
It odd how this always comes up, especially since the answer, for thousands of years, has always been the same. There have really only been a couple cases when humans haven't rebuilt their cities: Angkor Wat and the mayan cities... and even in those cases the land around continued to be inhabited, just in a different way.
Perhaps the best story comes from 396 BCE. Brennus has just sacked Rome. The damage is pretty substantial, as you can imagine. Most of the city was burned. The survivors are sitting around in this ruined, indefensible place, wondering what to do. Now, it just so happened that the Romans had sacked Veii six years before, after a ten year siege, and taken or slaughtered the population. That *was* a defensible spot, and some romans had already moved there. So the Romans are sitting around, saying "maybe we should rebuild in Veii. The Gauls might come back." Just then, the ragtag remnants of a legion walk into the burned out central plaza, and figuring this was as good a place to stop as any, sit down and rest. That decided it, and they rebuilt Rome on that spot. Just like every other place has always been rebuilt.
I'll rest my case with this little factoid. Years ago, I had a girlfriend. She was born in the 1960s. In Carthage!
Thanks,
Bill