My understanding is that many early societies were quite egalitarian but they also tended to be relatively small. One area where decentralized power is not so

My understanding is that many early societies were quite egalitarian but they also tended to be relatively small. One area where decentralized power is not so good is warfare. Thus these societies tended to be conquered by their more warlike neighbors. This pattern repeats multiple times until the world is full of feudal monarchies, even though that system of government is relatively poor at building and maintaining infrastructure. Scientific and technological progress has been held back for thousands of years because this one system of government was better at killing their neighbors and in the end that was what really mattered.