Chronicle of an early social contract

In his new book The Origins of Political Order: From Prehuman Times to the French Revolution, Francis Fukuyama considers the origins of the social contract that formed the state, and speculates whether it could ever have been the product of a conscious decision on the part of a tribal society. He does not take this discussion where I thought he would:

     Thomas Hobbes lays out the basic "deal" underlying the state: in return for giving up the right to do whatever one pleases, the state (or Leviathan) through its monopoly of forced guarantees each citizen basic security. The state can provide other kinds of public goods as well, like property rights, roads, currency, uniform weights and measures, and external defense, which citizens cannot obtain on their own. In return, citizens give the state the right to tax, conscript, and otherwise demand things of them. Tribal societies can provide some degree of security, but can provide only limited public goods because of their lack of centralized authority. So if the state arose by social contract, we would have to posit that at some point in history, a tribal group decided voluntarily to delegate dictatorial powers to one individual to rule over them. The delegation would  not be temporary, as in the election of a tribal chief, but permanent, to the king and all his descendants. And it would have to be on the basis of consensus on the party of all the tribal segments, each of which had the option of simply wandering off it didn't like the deal.