Earth as a whole is essentiallly a closed system right? Nothing leaves except what we send into space and (presumably) no material enters earth except the some space debris.
Where does all the earth/dirt come from to consistently bury historical structure under ground across the world?
In: Planetary Science
One explanation is survivorship bias.
Many historical structures have been destroyed. Broadly speaking, anything above ground stood a high chance of being repurposed, demolished or exposed to weather etc etc. So much of what we discover tends to be buried because much of what wasn’t buried was destroyed.
Things get buried over time, sometimes deliberately. It is really only in post-industrial times (say 1800s) that we have large earth moving equipment or the broad availability to transport lots of material over long distances. Prior to that, the easiest way for most humans (ie not rich) is to repurpose nearby materials and burn/bury the stuff that isn’t useful. Then build over it. No one was going to spend resources to do much more.