Another idea that I find fun to think about, especially for fiction: What if those ancient humans weren't primitive creatures newly learning things, but remnants of a civilization making do with whatever they had left?

e.g. If everyone in the future uses always-connected AR glasses and personal AI assistants, would anyone bother to write much, "in the wild"?

Someone discovering a cool sightseeing/hiding spot may Instagram a few photos, saying "follow the arrows.", and we kind of already do that with geocaching etc. [0]

In the farther future, someone may only find the crudely-etched arrows, with no reason to assume that anything like the internet existed back now. :)

[0] https://en.wikipedia.org/wiki/Geocaching