> they had no way to evolve past this stage of development

That infantilizes them, in my opinion. Their state then was an early state of many people around the world that made different choices that lead to different results. They made choices, those choices had consequences, and no one decided to do otherwise -- OR, if they did, they failed and have been lost to history. But lets not remove their agency.

The environment makes a very real difference to what outcomes are possible/likely. It is hard to create a complex society if there is little food surplus and no real way to store food long term.