We stopped teaching math decades ago when we switched to teaching arithmetic. Therein lies the problem.
The top 20-50 urban school districts in the US put the education of students at the bottom of the priority list, if it appears at all. These districts are run by politicians, administrators and teachers who are interested in jobs, graft and "fairness". Providing a quality education at a reasonable price is not even given lip service.
It actually goes deeper. If the residents of these districts, the voters, actually cared about the kind of education their children are receiving things would be much different. The students, well aware of their environment, think paying attention and getting grades is "acting white" and therefore anathema to them.
The test results of these districts is cooked into this survey. Take them out of the survey and the US moves way up.