I think the fact that there was no single ruler in the stateless societies allowed them to endure for many centuries. No family had too much power than the others. The way they resolved their problems also helped them survive for a long time since it allowed them to peacefully talk about the issue without violence. They also had a very organized way to decide to who to pass down the possessions and property too. People were also separated into age-sets where they would pass stages of life with other people in the same generation.