The reason for the way civilization arose is discussed ,IMO, very well in 'Guns, Germs and Steel' by Jared Diamond
And yes, having what we call North being "up" is just like all of the really old world maps that conveniently had whatever country the map was made for as the center of the world. Other than being good PR and selling maps to dingbat potentates of tiny countries, there was no good reason. Just as arbitrary as North being up.
I wonder how the Aussies feel about this? All upside-down?