[rank0]

That same book claims that the agricultural revolution was responsible for human specialization. We were able to feed larger families/tribes and develop non-food related skills. Without agriculture, those extra people would've died aka "thin out" as you mentioned.

[imtringued]

Agriculture encourages large families since children can help out in the field. Meanwhile with a hunter gatherer lifestyle the amount of food that can be acquired is not limited by labor but rather by the local environment. The effect is that you have lots of people doing backbreaking work every day.

[s1artibartfast]

The two are not mutually exclusive. Are you going to boom and bust in both scenarios