I'd hate to tell, you, but this idea is really overblown.
In science, our scores are grouped with countries like Norway, Belgium, Denmark, and Ireland. We are better than Sweden, Austria and Spain.
In Math, we lag behind the top group by quite a bit, but our scores are grouped with Israel. Should Israel be apoplectic about its math scores? And by the way, don't they have a much smaller, more homogeneous population?
In reading, we are grouped with counties like the Netherlands, Belgium, Taiwan, Australia, Denmark, and Sweden. We are better than Switzerland, Austria, Luxembourg, Iceland, etc.
I guess the question is how well SHOULD we be doing? I can't think of any reason we should be doing significantly
better than those other countries I mentioned.
In fact, given our ethnic diversity, number of students who don't speak English, and income inequality, I'd argue that our public school system, if anything,
outperforms its valid expectations.
For example, we rank 34th in life expectancy. So, hey, our schools outperform that bar by quite a bit.
I think you are laboring under a false illusion that relative overall quality of life in the US is much higher than it is.
I'm sorry, but we've spent the better part of 40 years losing ground to the rest of the world on all kinds of quality of life categories. It's unrealistic to expect education to be isolated from this phenomenon.