That isn't the headline you probably saw, but it really is true. The problem is that demography matters. Once this is understood, many things become clear. Thankfully, Tino at Super-Economy has done us the hard work of breaking down PISA scores by country of origin, comparing European Americans with Europeans.
When you look at things this way, one can see that Americans tend to do as well or often better than their cousins who stayed home.
Tino has positive comments about the American school system, although I might disagree that having more expensive textbooks makes for better schools. However, there really is not an overall performance problem for American schools as measured by tests like PISA. I suspect we could get the same or better results for less money, but a fundamental obstacle is accepting that demography matters.