A huge part of the problem is the whole "burning every Maya book" thing that some spanish dudes decided to embark on. Various ethnic cleansing campaigns over the last two centuries or so, not to mention the impact of disease.

Its a real tragedy the colonizers didn't think to preserve the world they were conquering.

There were a large number of of Incan markets at elevation in the Andes. If your civilization was built around the productivity of terrace farming - then people will be living at high elevation.

I mostly agree, it’s weird.

However the region has little in the way of flat ground and the nice flat valley floor is very very flood prone.

Top photo looks like mining to me.

When the barbarians come to raid, it’s much easier to tip a rock over to stop them.

“I have the high ground” became a meme because of the Star Wars prequels but it was a legitimate force multiplier.

The US has a military strategy of air supremacy, notably different from air dominance, because of how easy it is to win when you can just let go of a rock and it’s guided to your enemy by gravity.