I’m really not sure, if you look at things before the 20th century it’s difficult to see a pendulum swing pattern. That works relatively well between the 20th and 21st centuries, but I don’t think we can see it as a general rule. It’s also pretty dependent on the region you look at, and movements you decide to take in consideration or filter out. There is just so much room for biases, it’s easy finding a pattern because that’s what our brains are good at doing, but it doesn’t mean it is predictive of anything

That being said, this video from Three Arrows (aka Dan Arrows) “America coming Weimar moment” has interesting things to say on that specific comparison: https://youtu.be/CFDDf48nj9g

A lot of folks forget that ancient Egypt existed for thousands of years without major changes.

Pre-industrialization, civs tended to come and then go(dispersing with other groups), as power structures came and went.