Further Archaeological Evidence that the First Megalithic Builders Were One Global Civilization

Whatever the reason they disappeared (left the planet with all the tech that wasn't immovable while leaving behind some people as an experiment...or wiped out by a catastrophe so complete that only the truly megalithic structures and small pockets of survivors remained), the civilization that appeared after them was much less technologically proficient.

For thousands of years each successive civilization (in the video below it's clear that the culture responsible for megalithic structures in Peru rose and fell prior to the Wari culture which preceded the Inca) gradually declined in technological prowess as the remaining knowledge from the megalithic builders slowly eroded. It's only been a relatively short time since tech advancement has been going forward instead of backward.



We're probably damn close to the level that this "Megaculture" had attained.

If so, it brings up a few possibly important questions.

1) If the Megaculture were Humans that were almost completely wiped out by a catastrophe, how long did it take them to reach the level of tech that they had before their demise (measuring from their lowest level to their end)?

2) Is it logical to assume that, from a similar starting point, post-Megaculture tech would, on a worldwide, overall basis, most likely advance at the same rate as Megaculture tech did from its low point?

3) And, understanding the cyclical nature of the Universe, how likely is it that the time from population decimation and abrupt end of peak tech due to natural catastrophe is a regular cycle?

4) Is it possible that Human level of tech achievement can be used as a signpost marking a cyclical cataclysm on Earth?

Just wondering.