Actually 2/3 of the planet is inhabited by people living in a "civilized" empire/country. The rest is inhabited by tribes and bands of nomads or primitive agriculturists. That is not that far off.
The fact that there have only been two major wars isn't that bad either. Surely there have been numerous battles fighting the "uncivilized" barbarians. Those barbarian villages that were destroyed are also wars, sure it is a one direction war, where an huge empire with advanced technology is destroying a bunch of pesky neighbors that, at most, can pillage and plunder the fertile lands of the civilized empire, but history is full of such wars.
So with a little imagination the game is not that off.
What I found really off is the fact that some civs that did not have a glorious history IRL are so OP in the game. Like the Inca who did not even had writing by the time the Spaniards arrived, are super good on science in the game. That is ironic. This works both ways, like the Romans who maintained control over the Mediterranean basin and great areas of inland Europe for hundreds of years, are a pretty bad civ in the game.