One other quick thing I’ll mention.
It was too soon to expect that black children in general could catch up to children of other races, in so short a time, especially because they still faced many extra challenges.
Black people were making inroads, just as many immigrant groups have, through manufacturing jobs, but just as they did, manufacturing started being shipped overseas, as we know.
At the same time, too, secular humanists, including the secular humanist corporations, started undermining Christian beliefs, with greater and greater success.
Something that is coming to my notice more and more is how people do not have basic respect for rules anymore, as they used to, in which even if they broke a rule, they’d feel some guilt about it, or at least know they should.
But today, people use the “situation ethics” and moral relativism of not respecting rules, but just asking “will my actions hurt anyone,” and if they can’t imagine it will, then they feel they can morally break rules. That really makes for a narcissistic, amoral society.
How many generations will be needed? Keep in mind that we have East Asians coming in and being fully assimilated into the middle class within one or two generations.