The R complex. It is an integral part of our brain, and it isn't going anywhere for a LONG time. It is the source of territoriality, pain, aggression and domination. You can see traits shared by all animals that have evolved from early reptiles ( The R complex = Reptile complex ). They all have hierarchies and leaders. There's a leader of the pack, and many animals will have the alpha-male chief fight with other animals to decide which one is the chief. We have the same needs for structure and leaders. ALL human civilizations have government. Some had monarchies, some a chief system, some would fight for leadership, some were born to it; but there has always been a leader.
If there isn't a leader, it's because the species is a solitary one, living alone and only meeting to mate. Humans, however, are a social species. IT's been shown time and time again that humans NEED social interactions with others. People without it often go batty.
Our brains make us need to be around others, and as soon as there is a group of people interacting, there is government. As soon as two or more people decide even the most basic of rules, like a mutual agreement to not have at each other, government is formed. It is a small one with near nil bureaucracy, but it is not anarchy.