I'm gonna go out on a limb here....
I think we seem to believe as a society that schooling is supposed to be able to elevate everyone to a baseline of education. That, somehow, regardless of individual, intrinsic values, if a student didn't meet the base expected bar, it's a failure of the schools.
Now, I'm not trying to say that some people are just dumb and good luck, schools can do no wrong. There's plenty wrong with the education system.
But after college I realized that it's really on the individual to make the most of their education. Schools can't make that happen, it comes intrinsically from the student's desire to do well.
My parents read to me as a kid. Possible genetics aside, I think I was reading by about 4, which set me up for a life long love of literacy, and all throughout school that was the one thing I excelled at above all things, reading way higher above my expected level. Yet I was terrible at math. Just couldn't wrap my head around it, struggled with basic math skills for a while like division, etc....
I got a tutor, because it was important to both me and my parents that I at least pass the base level requirements for high school. It cost money, it took time, and I can't say it made all the difference.
Looking back, I can easily see what was going on: I really only truly applied myself to the stuff I cared about and felt good at. The stuff I didn't and wasn't.....I did but I did with this air of frustration and anxiety. And because schools aren't well equipped to spend more time with you on the things you struggle with (as opposed to the things you're good at where they can and will immediately fast track you), it takes additional time and effort from the parents, possibly outside of school, to make up the deficit.
This isn't a "blame the parents" thing either, but I do wonder in the last 35 or so years if there's been a shift in how much effort parents invest in to their kid's education and intelligence before they get to school. Do parents read to their kids as much as they used to? What values to parents instill in their kids? Do they get the talk about why schooling matters and why caring about it matters?
I wasn't a great college student, but I had aptitudes and I leveraged them. Looking back, even there, my thirst was for knowledge for its own sake, rather than learning for what it could do for my career. As a result...I was good at and rapidly completed the course work I liked, and got average marks on the stuff I didn't, and I didn't do job fairs or career fairs or internships or any of that. I didn't actually want a career, just the degree, because my thinking was the degree was all that really mattered. That somehow, ignorantly, I could do no planning or have no goals up until getting that degree, and that somehow magically, I'd land a good job after I had it. Internally, in my uh "senior year" I knew that was bullshit. I started looking into getting placed in my major at some job but by then it felt too late, and again, I wasn't sure I actually wanted that. So I went out of college kind of like a fart, rather than busting out and in to something. I don't blame anyone but myself for that. I liked learning but schooling couldn't make me give a shit about my actual future. Something I do kind of regret now.
So again. I don't think there's no problems with modern US schooling. But I think we have LONG avoided placing some blame rightly where it belongs: students and parents and the values or lack thereof. Criticizing people's kids, or their parenting, is considered taboo in America. Raising your kids how you want is sacrosanct, and everyone's an angel who has had the best preparation and motivation to do well in school, so OBVIOUSLY it's the school's fault. You can't MAKE kids give a shit, they have to LEARN and be TAUGHT to give a shit and about why they should give a shit. That is down to the parents IMO. Even with a terrible school system, a student who cares about their education will excel. College taught me that while teachers are a great resource, they're not the primary resource. There's a wealth of knowledge out there to be had so that if you ACTUALLY care about writing a well researched paper, or improving your accuracy and understanding in math, or to broaden your understanding of history, that is all out there for the taking. But most people don't view school like that. Kids view school like some adults view their dead end job: you punch in, do the minimal that you need to be considered effective, and spend most of your time thinking what you're going to do when you're not at work. That's an attitude we gotta change if we want better students, and by extension, better citizens going forward.
Another thing that dawned on me recently at my own job.....I think I do the least learning and retention when someone smarter than me is standing over my shoulder, waiting for me to understand. I saw it in college all the time, manifested in people's lack of desire to speak up in class, that glassy-eyed look of anxiety as you watch the gears in someone's head as they desperately try to formulate the right answer on demand.