Take a completely random sampling of 1 million people from populations all across the world. And in fact, take them from the day of birth to avoid any sort of early biases (actually 'harbor' the parents from the day of conception to avoid any sort of prenatal differences). And now put all of these million people on a completely homogenous and equally fertile chunk of land on an island. Raise each and every single one of them identically until they are of an age to take care of themselves. Give each and every one of them the exact same amount of starting 'capital' and set them free to achieve as they will.

200 years later, with a population that's multiplied several magnitudes over - would you expect to still see a completely equal people? I wouldn't. People are different. And each child that is born is different, even when born to the same parents. Even identical twins are no longer completely identical by the time of birth. These differences express themselves in different ways (and wow was that the most tautological statement ever), but the point is that I think it's highly illogical to expect to see equality.

Out of genuine curiosity, do you disagree?