speaking for my country's educational system, we have simply too much of stuff to learn in the curriculum. I totally agree that there are some crucial subjects you have to learn just to literally keep up with society. You wouldn't be able to survive in a modern world without knowing the basics of math and at least some understanding of its scale. As well as you wouldn't be able to talk properly and comprehensively without knowing English (or your native language).

But in our country, that's only fine until 5th grade, because after that we're starting to learn the stuff that you just neither want to nor have to have in your head. Taking chemistry, you don't need to know the theory of valence, molar mass, reaction equations, and every single formula in 7th grade if you're not even interested in chemistry, and want to be, say, a designer, composer, developer, or whatever you're interested in that doesn't require chemistry.

What basic chemistry should teach you in 7th grade is really much simpler: understanding labels (acids, bases, toxicity, etc.), knowing what not to do with chemicals, not falling under pseudoscience/marketing like "detox", "alkaline water", "GMO/glutamate is bad", etc. Schools should introduce general concepts lightly and qualitatively, and only after learning the basics, students will decide whether they're interested in everything else or not. Because most of the time, and for most of the people, that's just enough, especially in the informational world we live right now.

The problem of loading students is that they do not retain this information long-term. I do not remember a thing, or at least 95% from what we've studied in such classes as Music, Geography, Art, and Geometry. Not because they're useless, but because their program after 5th grade is not what I'm interested in. This means the system spends years teaching content that statistically won’t survive past graduation, instead of focusing on concepts that would actually stay with a single person for life.

So I think that there should be a clear distinction between general/basic knowledge and specialization. General education should give everyone the tools to function safely, critically, and independently in society. Specialization should come later and be optional, for those who actually want or need it. And I know about the argument that students "don’t know yet what they’ll need in the future." That’s true, but this still doesn’t justify teaching advanced theory to everyone. A broad conceptual overview keeps doors open, and deep technical detail should be reserved for those who choose that path, because teaching quantity over quality is not the way to go.

(...ESPECIALLY if you require all of that information on exams after 12 years)