You’re living in a fantasy. Real life, children need parents. Parents who are lazy think the schools will teach their kids everything. It was never true.
Real life, children need parents. Absolutely. Public schooling? Good luck. I think the OP shows you the morass.
The true correllation between parents and education is how valuable parrents believe education is. In our school district we tested incoming kids in math ability. There were three groups. Those who were placed in Geometry as freshmen, those who were place in normal Algebra as freshmen, and those who were placed in individual study to master Adding through Percentage problems.
They came from distinct neighborhoods. The Geometry classes had extremely wealthy parents. The Algebra kids had middle class parents, and the weak math students had blue collar parents (or likely only one adult to the household). It was not hard to see how this happened. The wealthy kids neighborhood school gave pages of homework each night. The middle class kids had maybe a page of problems each night and the blue collar kids got little homework and were not held accountable for any they were assigned.
BTW, I would say that race had little to do with this, but the district had about one third minority kids. Most of them were not living in the very wealthy neighborhood. (I lived in one of the poorest neighborhoods myself, but we still had much more wealth than most of the country — we lived in the SF BAy area — for a partial reference)
There were minorities in the middle class comunities and the blue collar communities but at school there was little divisive behavior. When I taught in the catch up math class I had parental assistants — and I had to teach them how to explain some of the more difficult problems. There were also many kids who came from one background and made it into a higher or lower class level, High achievers could go as far as they wanted in the high school I am talking about.
One last comment, when we went into a period of layoffs, I was laid off. The union and the school district went entirely by seniority. So my 9 years was not enough. (They laid off through 12 years of teachers.) I felt that I was doing OK, and was forced to go back to Aerospace Engineering. I really liked teaching but I could not buck seniority but I do know that the Teacher’s Union does not prioritize the kid’s education or the kid’s school experience.