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>.
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.
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?
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.