Here is a quick tech tree of how a suggested tribe could evolve after the prelude.
No Evolution: Barbaric
Classical Economics (Economy)
Guild (Economy, Secondary Industrial)
Nationalism (Economy, Secondary Political)
Monarchy (Industrial, Secondary Political)
Tyranny (Industrial, Secondary Economy)
Republic (Primary Political, Secondary Economy, Secondary Industrial)
Capitalism (Primary Economy, Secondary Political, Secondary Industrial)
Religious Statehood (Primary Religion, Secondary Industrial, Secondary Economy)
Empire (Industrial, Secondary Political, Secondary Expansionism)
Communism (Industrial, Secondary Economy, Secondary Expansionism)
Of course this suggestion isn't completely limiting tribes, it only benefits tribes more in certain areas, and tribes are free to switch with little delay. Evolution over time will allow more government types become available, and of course, the above is not a true suggestion, only an example of how a government evolution could possibly be.