The Halls of Amenti Have Been Discovered Under the Giza Plateau

[Byrd]

On a serious note, how about the pyramids being giant lightening rods/conductors? Once struck, any physical body is then removed from the sarcophagus having had the soul and spirit taken up into the afterlife. Would account for the lack of mummies.

Limestone is an insulator, not a conductor.

Giza gets about 1 inch of rain a year.

Tomb robbery (and priests shuffling mummies to more secure locations along with known evidence (from ancient Egyptian trial records) of thieves burning mummies -- AND poor mummification techniques (mostly bones until you get to the New Kingdom) accounts for it.