Why There's So Much Political Equality and Liberty in Societies?

There's no way for any person or coalition of people to really dominate any one else, even if they wanted to. And since the band is always moving around, there is no way to hoard or defend resources. So anything that people really need can be found or made or acquired in exchange by more or less any one - with the exception of large game which usually only certain people are physically rong enough or skilled enough to acquire.