1) Geographic escape of the regression to the mean.
2) Duration of planning and voluntary organization required to preserve cooperation (see also inuit peoples and amerindians)
3) Utility of people in scarcity vs disutility of others in density,
4) Geographic (horizontal) range of trade (information transfer) on the eurasian continent.
5) Temperate gradients that can only be defeated by tools, vs disease and tribal gradients that are defeated by reproduction and early maturity.
6) Negative pressure on the less able (shorter term) in winter climes. I mean, winters are the best agents of darwin.
7) The difference between central management of irrigation and therefore centralization of capital (fertile crescent, indus river, yellow river), and the lack of such need (or utility) in both europe and the plain and the black and caspian seas. (Our farmland is bigger and better and more distributed meaning capital and defense had to be distributed).
8) Combining the european wheel, with the anatolian bronze, with the steppe horse, and therefore freeing man from his bodily limits and creating a civilization that mastered ‘ooda loops’ (maneuver, markets) at every level.
9) Hence we are rarely first, but we are always fastest, because there is no faster way to adapt a society to constant change than ‘markets in everything’ adjudicated by the common law of tort (property).