The thing is that upper/middle class parents value education more than lower class parents (on average). Unless you take the kids completely away from their parents (horrible thought, was somewhat tried in the GDR), the former kind of parents will find a way to give their kids valuable lessons, even if it is just sitting on the sofa and reading a book.

I recently met a woman that brought her son to the first day of school. Not only did all her manners signal "lower class" when she talked to the teachers, but also she explicitly mentioned that she thought the kid would not fare well in math. I also saw the boy and he did indeed not behave like the brightest, but who knows what lies under the surface? That mother basically made it very hard, if not impossible, for her kid to ever reach higher education. She won't search for tutors, even if she would not need to pay it. She will be content with bad results. It's really sad to see, but I think there really is no way to fix this inside the school system.

Regardless of class considerations, my point is that the education rat-race is prevalent in places where an average job doesn’t guarantee a good standard of living and/or where there are strong winner-takes-all dynamics, so everybody has to play the winner-takes-all game from the age of 6. I know people in London who have become catholics so they can get their child in a catholic school (for whatever reason they are considered better than others), the rat-race for them started before the child could even attend preschool.

From my experience of Germany and of the UK, I’d say that a mediocre job in Germany gives you a much better quality of life than it would in the UK. So you don’t have to get your child into the super-fancy Montessori nursery with the highest rate of alumni attending <German-Oxbridge>.

> The thing is that upper/middle class parents value education more than lower class parents (on average).

I don’t know if I’d agree with this. It might be true in some contemporary societies but I don’t think it is universal. But I do agree with your other point, which is that culture will always dominate other factors in determining how much education parents seek for their children.

The specifics aren't as relevant as the acknowledgment that there are cultural factors and feedback loops that are generally not part of the discussion (and might be omitted specifically due to concerns about stereotyping and bias).

How involved in your kid's education can you be if you work 60+ hours a week with a 90 minute commute each way? How do you expect kids to focus or even care about school if they come from a violent neighborhood or a broken home?

Foreigners always think the German school system (Hauptschule, Realschule, Gymnasium) is 30/30/30 but in reality it's more like 5/15/80. Almost every student is going to the gymnasium by default nowadays. If you are not a total dimwit then you can get in and as a result, the standard of education is not great. I remember I had a student in my senior year English class who couldn't even deal with the simple present and still got a B. The discrepancies in performance between students on a Gymnasium is probably greater than between Gymnasium and Hauptschule. While the average education on a Gymnasium may be better than on a US high school, the US high schools are actually much better for capable students because the AP system allows them to get away from the window lickers like the Gymnasium was initially intended to do. The Realschule then is for all the people who _could_ go to a Gymnasium but their parents didn't let them. Finally, you have the lowest 5% in the Hauptschule who are practically outside of society. They are functionally illiterate or have such grave behavioural problems that many of them are unsuitable for even the most simple menial labor jobs (think stealing, regularly skipping school, arriving hours late for a job interview, assaulting classmates and coworkers, etc).

Since Gymnasium is already so easy that almost everyone can get in, the only people who end up at a Hauptschule are those who grew up "outside the system" in an environment that practically prevents any kind of education. They live in a ghetto where everyone receives social security, are often immigrants with parents and friends who don't speak the language, have to deal with domestic abuse and bullying everywhere... you get the gist. Even the bright students among them who initially do well are continuously put down by their parents and peers while the teachers are hopelessly overwhelmed just trying to keep the worst of them from literally killing another.

Wikipedia says ~28% attended a gymnasium in 2010: https://en.m.wikipedia.org/wiki/Gymnasium_(Germany)

28% of precollegiate students, which includes preschool and grade school... If you only consider secondary education then Gymnasium and Gemeinschaftschule account for 60% of students.