This is actually not a very relevant question, since it's useless to compare the races as if they are - or should be - the same! They were created different on purpose, to allow spirit to incarnate and have different experiences.

Spirits seeking the experience of "making achievements" would of course not incarnate into a vessel not designed for such a task. But the purpose of making achievement is not the only purpose spirit is interested in.

If you open your mind and observe black people without judging them by the white measuring stick as it were, you might catch a glimpse of what they are about, and what purpose incarnating in such a vessel might serve.