Well, as much as I felt comfortable with the thesis statement, I must demur. In point of fact, human pre-history is more complicated than Manfred F. Schieder allows. For onc thing, the "tribal leader" as we understand it was a recent invention. True enough that apes have Alpha Males, but you must realize that today's so-called "primitive" peoples have thousands upon thousands of years of history underneath them. If you want to construct an empirically consistent and theoretically narrative explanation of our own condition, then you cannot go farther back than Sumeria 8000 BCE. Not well explored is the fact that the bow and arrow allowed a woman or child to kill a hunter from 50 paces off. Thus, indeed, most (modern) hunter-gather societies are egalitarian. The problem remains with the hunters of the Yamoamo who deny weapons to the women whom they subject, though, interestingly, they reward a male child who strikes his male parent.
Basically, this is all a lot more complicated than mere ideology.