It seems like many earlier civilisations came about purely because the starting conditions were ideal, although Egypt is likely the best and longest lasting exa

It seems like many earlier civilisations came about purely because the starting conditions were ideal, although Egypt is likely the best and longest lasting example of this. Even into late antiquity Rome was heavily reliant on North Africa for wheat production, and it wasn't until the medieval period that techniques were discovered allowing for better wheat production in the more colder and northern climates of Europe. Contrast this with steppe tribes, whose main advantage seems to have been good leaders and not having cities they were required to fall back to and defend.