Gene: By the way, the worsening of conditions under agriculture is a well known fact, not a oddball opinion of Clark’s. Agriculture allowed a big population increase, but at the cost of a harsher lifestyle.

Sure. Of course, that still leaves open the further, and probably more interesting, question as to why the population increases enabled by agriculture outran the capacity to produce the necessities for comfortable living. I suspect that the answer to that question has little essentially to do with agriculture, and a lot to do with some of the species of vermin that were able to break in and feed off of the surplus grain and meat. Specifically, the professionalized military and theo-political classes.