Why is this a "problem for the American education system"?
What else would you expect?
Education is not something that is done to you, like penicillin for strep. It's something that students do themselves (with guidance, of course), to the natural limits of their interest and aptitude.
One look at Mexico, or Guatemala, or El Salvador, and you would predict that their citizens would lag substantially behind Euro-Americans, whatever the "system" does or does not do.
Exactly! Some just don't have it in them. Liberals ignore the basic facts, and it all goes downhill from there. Like trying to fasten a screw with a hammer...