> It also doesn't seem to work given where the US ranks globally in education.

This is true because this isn't necessarily "the norm". Its very common to have this kind of life, but there are also a ton of kids who aren't as focused on their academics, who don't take AP classes, who aren't involved in clubs and sports. Only a little over a third of students take any AP exams, and only a bit over half of those end up taking multiple AP exams.