A good question. I'm on the record in calling prehistoric, shamanic-animistic societies child-like in certain respects. So hunter-gatherers would have been heroic in animalistic terms. Just surviving in the face of nature's monstrousness is heroic enough.
But that kind of self-reliance isn't what I mean by "maturity." I'm talking about existential maturity, and it's easy to be heroic when your view of the dangers is narrow. It's like being a hero in the Matrix, when you don't realize you're really a battery for machines, or a brain in a vat. Presumably, the hunter-gatherers would have had no scientific understanding of themselves or of the universe at large, so they lacked the threat of existential alienation. The maturity I'm thinking of depends on that modern threat of excessive knowledge. Prehistoric and late-modern consumers would be infantile in different ways. Maybe that comparison is worth writing about.
