This seems... maybe too handwavy. His core theory is that "intra-culture violence keeps populations down, ergo there's no food pressure, nor impetus to increase food production". And the evidence there is quite frankly really weak. He cites just one number (~20% of the population studied died from violence), and that isn't extrapolated in any way to actual population size estimates.

Also it seems to ignore the Darwinian angle here: it doesn't matter whether or not a culture "needs" to develop agriculture, the second one does its overwhelming size will destroy its neighbors. We see this effect with damn near 100% rates everywhere in the world it happened. So that seems like a poor analysis. Really at best this is just arguing for an unstable equilibrium waiting for someone to start planting.

I dunno. This is heavy on the "feels right" and really light on the analysis. I'd steer clear.