You know what I think the problem is? Americans on the whole just don't care about public education. Either in terms of quality or equity.
Public education, public healthcare, public transportation, public libraries, public lands.
Decades of the Republican party screaming that government is the enemy while gutting every public institution that it can get its hands on has led to a real, tangible decline in the quality of public services.
Then from here you get into a vicious cycle of "Wow, our train system is horrible. But I'm already paying for my car; I don't want to have to pay for that chump who can't afford a car to get to work." Or "What a shame about the state of our local school. But I'm already paying for little Billy to go to Catholic school. Why should I pay for the neighbor's education as well?"
Not sure about how we get ourselves out of this mess. But I feel like just generally giving a shit about our neighbors and communities would be a good start. Seems like we're heading in the wrong direction for the time being though.
Tracking happens late, at entry to high school (grade 9), where they split you up into academic, regular, and vocational tracks. From there on things move at a more respectable pace, at least in the academic track. But at that point the top-track students are already years behind their peers in other systems that moved faster and tracked sooner. I would guess the top students coming out of high school are about two years behind students in academic tracks in other countries, like the UK or Germany.
The public school I went to offered 100+ elective courses on different topics from law, and philosophy to computer science, industrial design, and even hairstyling. We had access to great teachers who took on project-based approaches to teaching that made the lessons more enjoyable. For example, when my Physics teacher wanted to teach us about vectors, he put us into groups and gave each group a sheet of vectors and a tape meter. We had to travel in the direction of each vector on the sheet until we got to a point in the school where he had hidden a sheet of paper and when we took that back to him, he would mark our assignment as completed. After that assignment, everyone in my class had a much better understanding of vector arithmetics.
Students who will attend a post-secondary in other countries will end-up redoing most of the advanced math and science they did in high school in the first-year of university anyway. For the rest of the students, those extra science and math courses will just be a waste of valuable time that they could have spent learning more useful skills.