Private, elite prep schools and colleges in the US are the best. The average college or high school is dismal compared to the rest of the world. We consistently score below the average of OECD countries.
For what it's worth, I didn't go to any elite universities and I make less than 35,000 per year, so I don't have a horse in this race.
What I'm saying is that if you actually compare people with similar demographically-expected IQ and socioeconomic situations, Americans stack up fine. It's the extenuating circumstances that drag the overall averages down.
All that really means is that overall averages across 300 million people aren't that useful.
And if your point isn't race or culture, but of economic disparity, that is sort of my point.
The US is a uniquely diverse country, and such a diverse country necessarily will have a tough time competing in average performance scores with better countries that are not diverse and, instead, have a quite uniform culture. So, right away on average scores, the US will have a tough time competing with much of Europe and the better Asian countries.
Also understand that the famous, prestigious US universities -- Harvard, Princeton, Yale, Cornell, MIT, Johns Hopkins, NYU, Columbia, most of the SUNY schools, most of the Big Ten, CMU, Chicago, U. Washington, most of the University of California campuses, Stanford, Caltech, University of Texas, Rice, Georgia Tech, etc. are RESEARCH universities and do not concentrate on technical or vocational training for software developer positions where H1Bs are common.
Okay: We're considering education quality and using test scores as evidence.
Well, it is Social Science 101 (my wife's Ph.D. was in mathematical sociology, and my brother's Ph.D. was in political science) to control on other likely explanatory variables.
So, an obvious candidate alternate explanatory variable is culture of the country of the recent ancestors of the students.
So, to compare education in the US with that in, e.g., Japan, we should see how (A) US students of recent Japanese descent compare with (B) Japanese students in Japan. So, now are holding culture reasonably constant and, thus, doing better comparing the schools and whatever else we have not controlled on.
Not to control on culture would be grade F in Social Science 101 and give total garbage results.
I.e., no fair blaming the education in the US when the real cause of the differences is culture and not the education.