Everything else should be about exposure. So children are lectured on science, history, or whatever other subject; but they don't actually need a grade in these subjects during elementary school. This would reduce the work burden on students and teachers. The only purpose is to light a spark in those with true curiosity.

In high school, students should be able to choose topics of interest that they learned about in elementary school to do more intentional learning with tests and grades. Everyone else continues on a general path with the core subjects being tested and non-core subjects simply being lectured.

In college, those who chose a specific focus in highschool accelerated their learning for that subject. For others, if they didn't find anything interesting, they can go into a trade or whatever else they choose. If they are late bloomers, they go to college and cultivate their newly found interests with a larger back log of pre-reqs.

There's no point in "teaching" children things that they immediately forget only for them to go on to become a generic office worker or retail employee. We should cultivate those with the desire to be cultivated, and stop pretending that it's actually feasible to have an entire society of "intellectuals." There is a place in the world for those who don't care about learning, but there is little sense in throwing significant education resources at them.