Whether Hancock is a celebrity is neither here nor there. Proper science is supposed to be above personal attacks.
There are funerary temples lousy with inscriptions outside, but anybody can build those anytime. Crypts elsewhere are scribbled throughout.
We still know very little about the pyramids, so cannot contradict speculation. The official story / timeline is just one such.
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.