The problem with the K-12 system is that it's just _bad_. There is no drive for excellence, so students that don't have engaged parents are just coasting. In some places (Seattle) you could graduate with a passing score without even attending the classes and randomly filling out the tests. Then there are busybodies that try to cancel math and magnet schools because they're racist (see: California).
There's a lot of variability here. The Seattle and California models are baffling to me. Totally agree that the US system is largely focused on irrelevant (or immutable) things. I have a kid in highschool now. His peer group is very, very impressive. Multiple perfect scores on the ACT every year. ~55% of the highschool is English-language learners and 60%+ is free lunch eligible (meaning poverty level or close). There's an engineering magnet program that does really, really cool stuff. The school was on lockdown 3 times last year for gang fights.
It's a tough environment, comparatively.
This is really apparent when you look at college admission tests. In the US you have SAT tests that are trivially easy to pass with perfect scores (more than 2% of people get them!), and ACT with a bit more reasonable 0.22% of perfect scores. In China you have Gaokao where _nobody_ ever got the perfect score, in Korea you have CSAT with something like 5 people a year getting perfect scores, etc.
I have a different take! What's the point of a test that nobody ever gets a perfect score? I guarantee you that I can design a test that nobody ever aces, but it also wouldn't be worth anything. I think there needs to be a middle ground between overtesting, teaching to the test, and tests being the be all and end all of education, and the loosey goosey approach one often encounters in the US (most commonly among leftists) that thinks all testing is bad and racist and invalid and hurts kids.
Another thing to look at is the competitions. You can likely remember your high school's football team name, but you probably have never heard about your school's math olympiad teams. Schools in the US spend a lot of money on stadiums and gyms, but hardly any on academic competitions. It's the opposite in China and Russia. Nobody cares about the athletic performance, but schools actively compete academically with each other.
You are probably assuming the wrong things given the demographics of Slashdot and those few of us who have hung on for decades at this point! I was not on the math team, but I had friends who were. I participated in both Latin and Computer Science competitions (and marching band). Our football team sucked (I know this from marching band). But yeah, I'm sure a huge amount of money was spent on the gym and fields and athletics, far beyond what was spent on supporting the best academic achievers.
You will get NO argument from me that America's obsession with sports, from the cradle to the grave, is hugely detrimental to our society and culture.
I hope that the current mess with NIL, paying college athletes (I will NOT call them "student athletes" -- what a joke) forces some or many schools to back off on their sports expenditures and focuses, but I'm not holding my breath.