There is a lot of labor in building things like buildings, much of it is clearing out the land to start building on it. If its already clear of trees and all you have to do is just 'level' it for the first floor, then you'll build your building right on top of the previous one. There are also things like sewers and other parts of the city which are easier to build by essentially building a raised roadway then trying cut and cover.
Now look at the pictures of Aleppo or any other heavily damaged, mostly masonry of some form, city. You've got piles of rubble. Its easier to smooth that stuff out and build again on top than it is to try and haul it all out, re manufacture it and bring it back in.
Also, you could move home locations but still go to the same market, tavern, workplace, fields, etc, and be located there, or just tell your old neighbour you moved.
These city locations are often abandoned for hundreds of years at a time
https://www.theatlantic.com/magazine/archive/1997/04/undergr...
Places like Troy, which had millenia of habitation, basically ended up ontop of artificial hills (tels) of the garbage of previous generations.