[Apollo]

Europeans have a high degree of cultural variation within a geographical area the size of China.

So does Africa.

[wardaddy]

So does Africa if you include the Northern coast of Arabs and other Caucasian tribes....some of which are mixed to varying degrees with the Negroid tribes from the South but the difference in Africa is a North/South issue...or in a limited manner between the interior and the coast which had more contact with the outside world.

It's not much different than the Americas before Colombus. Yes you had the Incas, Mayans, and Aztecs but aside from those it was all a relatively similar cultural hodgepodge. And least we forget, all the vaunted American Indian cultures of note were subdued handily by a few mean as hell Spainards on horseback with primitive firearms. Ironically, the less advanced but hardier and simply tougher Plains Indians put up a much better fight proportionately.