Because there's a bias towards so-called "practical" math - arithmetic and accounting and figuring out things like price per unit. I think this started because curriculum was highly biased towards "real American" farmers feeling like they only needed enough arithmetic to keep from being ripped off by city-slickers, and then got perpetuated by high schools needing to churn out standardized factory workers, which meant that knowing how to measure things and do fractions and decimals got imposed.<p>There's also a huge "tradition" component to US public schools. Parents for generations have had cows when something changed. Look at the reaction to doing some small bits of set theory in the "New Math" of the 60s/early 70s, or the freakouts about not teaching phonics in the 80s, and the Core Curriculum conspiracy theories of 10-15 years ago.<p>Making computers and software like Mathematica, MACSYMA, etc, and pocket calculators and later smart phones turned the whole thing upside down. Memorizing how to do arithmetic is actually detrimental to understanding, it turns out, and knowledge of symbolic logic and algorithms is more important than being able to add decimals and multiply fractions.<p>To summarize: US math education was entirely practical, the curriculum dictated by either farming or industrial interests. Pocket calculators, computers and smart phones have made that "practical emphasis" look especially medieval because what used to be higher math, is now what is basic. This is abetted by US citizens preferring tradition in curriculum over all else.
I actually think Math, as it is taught now in US public schools, is taught better than any of the other topics. Why? Because there is a standard progression from one year to the next and the supporting tools/software are more refined than the related tools/software for Science, History, and English.
Low prestige, low wages, hard subject. Is this not obvious? Situation in
Europe and Asia gradually converging to US's as wage gap between private and
public sectors widen.