Here's a 'what if...' for you.

What if West, Schock, Bauval, Dunn, Hancock & others are correct & there was a progenitor civilisation, accustomed to working in stone, that spread across the Earth (& so had the knowledge needed to produce the maps from which those like Piri Reis got his data) that got destroyed by the sea.

And there is evidence that there were 2 & possibly 3 episodes of catastrophic rise in the sea levels. One when the mass of ice (estimated at at least a 1/3 of what was there) let go from Antarctica & again when the Agassiz Lake in Canada let go as the ice dam gave way all at once. There was possibly another (or it may have been part of the Agassiz event) when the ice mass floated at Hudson Bay.

Recently there has also been the realisation that the land masses are not unaffected by the presence of ice. When ice releases from land, or when it melts, the land under it will rise & there can be a seesaw effect where nearby land, forced up by the weight of ice elsewhere, will sink as the pressure is released from nearby.

For example, I think it's the west island in Antartica is currently lower than sea level because of ice but would rise back above sea level if or when the ice goes.

So, if the catastrophic end of the previous civilisation was caused in such a way, there would seem to be two possibilities -

one is the survivors ensured they moved as far as possible from the sea before planting new roots &, using the knowledge from the past, kick-started new civilisations.
In one fell swoop we'd have answers to a lot of the mysteries from the past - how the cities appeared with hardly any evidence of development, where we got wheat, rice & corn from, (you do know they are not like their relatives?) why the flood myth is so prevalent (along with stories of how each 'tribe' had someone come from the sea to bring them knowledge & civilisation) & out-of-time knowledge like number systems & astronomical information.

Another is only the sites far from the seas escaped total overwhelm & so they became the focus of the new growth.

It would also explain why the early civilisations we know of all built pyramids
& monolithic structures, how come they had the fascination with the stars to the point of laying things out for observation, & even why we have societies that appear with a swag of new ideas & processes then don't change or change for the worse over hundreds of years.

If the knowledge was inherited, there wouldn't be the creative background needed to ensure it kept on being renewed. They'd use what they're taught & over time lose the detail & skills as those who knew, or were taught directly by those who knew die off.

So in Mexico, China & Egypt, the child-societies would inherit knowledge & maybe try to emulate or reproduce the older 'Golden Age' but as time passed, they would lapse & stagnate until they reproduce the foundations of knowledge needed to understand the higher level they vaguely understood long ago.

Just a 'what if...'

__________________
* Never doubt there is Truth; just doubt that you have it!