I see what you're saying, but if the logic held all the way through, and you believe the previous commentor's claims about intellectually frustrated people, then the obvious result would be that those people were doing things like taking on ethics, math, religion, and science in concrete ways. I'm not an archeologist or anthropologist, but I don't recall any particular advancements in anything really, from that era. Better huts. Minor improvements in tools. Where were the windmills? Why didn't they come up with gearing for mechanical leverage? Long term structures and joinery?
I get that we have a lot of intellectual force multipliers now, so the achievement of a few propagates and impacts more than similar intellectual leaps in the, past, but given the kind of advancements we know one person is capable of making, there was remarkably little progress during all of this supposed leisure time.
'Soft' civilizations that didn't work in stone are nearly completely lost. Nobody going to find a knotted rope representing algebra or combinatorics lessons, or going to understand what it was without written instructions?
More on point, if all of these intellectuals were hanging out in the amazon, bored, why didn't they come up with long term data storage like clay tablets and writing? Why didn't they write their combinatorics proofs in stone? I know you're not really saying they had combinatorics, but a few millennia of frustrated brain boxes should leave some kind of legacy, especially in the totally physical space they lived and worked in.
I get that we have a lot of intellectual force multipliers now, so the achievement of a few propagates and impacts more than similar intellectual leaps in the, past, but given the kind of advancements we know one person is capable of making, there was remarkably little progress during all of this supposed leisure time.