In a lightly populated world where you could just run down the river a few miles and totally disappear slavery would be a difficult institution to maintain. Imagining that Egypt could be run as a gigantic slave camp is bizarre.
Even the ancient Hebrews didn't claim that everybody was a slave ~ just them ~ and they were working on a treasure city, not pyramids.
Yes it would, but that is not a description of ancient Egypt. Only the land for a few tens of miles on either side of the Nile was habitable. River traffic was policed (and taxed). And where did you get the idea that ancient Egypt was lightly populated?
Imagining that Egypt could be run as a gigantic slave camp is bizarre.
But we are discussing a Pyramid building site.