[moloch-hai]

They certainly would have been looted, if there were something to loot. But as noted, looters never cart out the trash. (Or, anyway, until recently, in order to feel more like legitimate archaeologists.)

Anybody can co-opt a spare pyramid and scribble it up. There is even an absurdly sparely applied term: usurpation. Usurping one of the Giza constructions would raise eyebrows, but the others could tempt, if in good shape.

Once one's immediate predecessor is securely dead, actually expending on a fancy interment is not strictly necessary, given nobody can see inside anyway. Lots of crypts were left comically incomplete, later. Even Menkaure's pyramid was not clad as specified.

Later they must have got the idea of having supporters demand to tour the crypt before it was sealed, to make sure things were actually done. You probably can determine which successions were ... unfriendly by how incomplete the funeral chores are.