I’m just guessing here, but aren’t the majority of dead humans underneath a lot of structures?
I would figure as a culture falls it is built upon and it’s people are under the new culture’s homes.
but i could be wrong.
I imagine would be hard pressed to find any town or city that is not sitting on some previous cultures settlement or burial ground.
If previous occupants found the site suitable for habitation- reason states that so would following occupants