My point is that the spectacular building skills and art of the ancient Egyptians c.3100-1200 BCE have never been duplicated. Progress is not a linear upward incline.
I'm not disputing that; it's just that I am interested in the motives of the destroyers, not the relative value of the destroyed.
The so-called civilized French army got to the Sphinx and destroyed its nose before they were stopped by Napolean himself. Alexander's minions and later robbers stripped the pyramids of all their alabaster and white marble facades, the tombs by then were largely stripped of all valuables.
I would argue that you are conflating vandalism and plunder with cultural extirpation. When the Taliban blew up the Bamyan Buddhas, they weren't trying to steal anything. They weren't out-of-control louts. They knew exactly what they were doing. What they were doing was a thousand times more evil.
If you want a non-Muslim analog for the destruction of the Bamyan Buddhas (and what an Islamist regime would do to Luxor), I'd point to the scene in Schindler's List where all the medieval Jewish headstones had been made into paving material.
The Egyptians might have helped, but they didn't build anything. There is ample evidence the Pyramids were already there before the 1st Dynasty and definitely before Kuhfu. All later attempts at pyramid building were met with failure and abysmal design. No one could ever again figure out the 52° slope.