Kurt Vonnegut: were pyramids built during times of Gravity Fluctuation?

today I was reminded of a book by Kurt Vonnegut where among many things, the gravity in the future is being manipulated by the chinese for mysterious purposes.

it becomes a popular distraction among american to build pyramids out of cars and so forth, as there are occasional bouts of extremely low and extrmemly high gravity.

so, I wonder:

Many people propose that the solution to magaliths and giants appearing in the fossil records is that the atmosphere changed due to the 'flood' or some other cataclysm or natural event.

I wonder if a slightly different gravity would be the cause? like maybe we had a smaller moon, or no moon at all?

I don't know. but it sounds interesting to me.

so far the best idea I've heard is the 'different atmosphere' theory as it has been used to explain the Giant Insects of pre-dinosaur epochs in prehistory.