Nitpick: the Darwinian war is only lost with total extinction, if much of the biosphere and 99% of humanity is destroyed but a population of 100,000 post-civilisation scavengers continue humanity, it goes on until the next catastrophe.

On a more serious note: hunter-gathering lifestyle is not sustainable on a longer timeframe in the sense that the rise of a technological civilisation from it is possible. Hunter-gatherers weren't susptainable on a century timespan because they knew the danger, it's more they didn't knew how to be wasteful on a scale that it didn't just affect fellow humans, but the whole of the biosphere.

_{*Lunatic*, n.
One whose delusions are out of fashion.}