This study says race trumps parenting or solid upbringing in lifting the next generation. For whatever reason, black kids who grew up with wealthy parents were much, much more likely to become poor - social mobility in the wrong direction - than their white counterparts, same circumstances.

I don't know that the reasons are all that clear. The book I referred to didn't really address this specific observation with affluent black families, but the other problem is, how do we break the cycle? Who's job is it to do that? Anyone's?

We don't get to choose our parents. Blame the parents, sure, but they didn't get to choose theirs either. The whole thing reminds me of a history of modern day Israel I read, beginning with the birth of modern day Zionism in the late 1800s. The father of it is Theodor Herzl, who's late 1800s cause in Europe was equality for Jews under the law. He finally got it later in his life, in France. And he observed that the condition of Jews in France did not change one iota. Equality under the law did not create equality in society. That's why he concluded that only a Jewish homeland could create equality for Jews.

It's hard to explain why. Your point is mostly about "pulling yourself up by your bootstraps". For whatever reason, and I think there are endless opinions on the subject, that seems to work better for some groups of people than others.