As much as I like anarchy and that kind of stuff, I think you don't understand simple survival skills. Say there is a mammoth, and 5 people with spears. One guy can't take it down, they all try by themselfs, they fail. Then, they have the AMAZING idea to WORK TOGETHER for the greater good of getting food. They kill the mammoth.
Ergo, working together is better than staying alone and complaining when people kick your ass because your alone.