In that case, that "core" of the population also doesn't need to know about benzene molecules, river erosion processes, history of some ancient kingdom and all

In that case, that "core" of the population also doesn't need to know about benzene molecules, river erosion processes, history of some ancient kingdom and all the other trivia they load you up with at school. So, to me, it doesn't really follow that the curriculum is designed deliberately to churn out low-to-mid skilled workers. If anything it seems like it was intended to produce people along the road to being relatively highly-skilled people, but the implementation is as if by people who think that advanced skills are just the result of coagulating enough trivia (though I think it's actually an iterated "you get what you measure" outcome, rather than educationalists who actually think that). Just like sometime who "learns" a language by drilling only vocabulary, this ends up serving no one particularly well - many people who would otherwise end up in trades have few practical skills taught and couldn't care less about benzene. Many people who would end up being PhDs in organic chemistry are bored rigid by the tedium of the process. As you say, it is a parental responsibility. But the school system has spent decades telling engaged parents that the correct way to fulfill that responsibility to provide rounded education to their children is by sending them to school, and it's becoming clear to some parents that the school system isn't actually upholding that promise.