Just because something has happened before, doesn't mean it's bound to happen again. All those countries have also had slavery and monarchies, but we don't worry about that happening again b/c humanity moves forward and certain things simply become impossible - this includes things like the return of nazism, communism, evil tyrants, emperors, juntas and whatever other anachronism you can think of

"nearly all the autocracies in the world with a higher [than $6000 ] per capita income are petro-states" http://thediplomat.com/2012/10/is-chinas-communist-party-doo...