Shortly after the great pyramids were built, Egypt underwent a time of political turmoil, with evidence pointing to some combination of invasion and civil war.

The next iteration of pyramid building was a “make Egypt great again” political statement, but without the skills. You can see this loss and gain in the quality of art and paints, in addition to the architecture.

Soon after that though, pyramid building was again abandoned as big loud pyramids failed to accomplish one of their goals - the protection of the Royal mummy and its property. It was just too much of a target for grave robbers, often being emptied out by the very workers who built it. This resulted in a transition to much more subtle, hidden tombs. One of which was undiscovered until the 20th century - king tut’s. (The rest were also found and robbed.)

The fringe theory is that the great Giza pyramid is much older. Those that are assumed to be the first pyramids, may actually be the first of the "make Egypt great again" period thousands of years later

What we do know is that the very best quality stone dishware, tens of thousands of pieces, was piled up haphazardly under what is supposed to be one of the oldest pre-Giza pyramids. Nothing known to be from dynastic times ever came close.