My point is that they are wrong about which parts of their good parenting are causing the good outcome, which is important because if I'm right then we should understand the problem more as a failure of society than a failure of parenting.

Of course anyone can be a bad parent, but being a good parent might require having a certain amount of material security and wealth. Not such a crazy idea if you think about it.

It’s a correlation to be sure. But also inter-generational family habits, like inculcation values of meriting good habits, e.g. discipline. Some families like that basic history.