One premise is that if a significant deficit in, say, wealth or education is created for a group of people, then it will be a persistent disadvantage that causes that group of people to lag behind.

Another premise is that slavery wasn't that long ago, relatively.

If, 150 years ago, we had person A start with $100,000 in inherited wealth, a solid education, a well-developed relevant skill in the marketplace, a well-established social and professional network, and a family with a good reputation. And then we had person B start with no money, no education, no marketable skills, no network, no family, no reputation...

If person A and B set out and lived their lives and had offspring, person A with the mentioned significant advantage over person B, I would imagine their offspring would be born into similar circumstances, with the offspring of person A maintaining an advantage over the offspring of person B because of all the obvious reasons people with advantages in wealth, education, etc. tend to maintain an advantage. The advantage may have narrowed (or maybe widened), but the advantage would be carried into the next generation.

Continue this forward 5-7 generations. What would we expect to see? I think we'd see line A maintain an advantage. The advantage may have narrowed (or maybe widened), but the advantage would be carried through generations.

Of course line B could "catch" and surpass line A. It's easy to imagine exceptional scenarios. But it seems probable that line A would enjoy an ongoing advantage.

And this scenario assumes a level playing field for descendants of line A and line B. I don't believe that's been the case in America for blacks and whites. Since the end of slavery, there has been significant discrimination against blacks, much of which continues to the current day.