Well, yeah. What do you expect?
We as a country don't value education. Teachers are hideously undervalued, not respected, poorly trained, and poorly supported. Our curricula are archaic. There are ridiculous and self-perpetuating disparities between "good" and "bad" schools that we seem completely uninterested in fixing. The push for "accountability" horribly undermines student learning, and favors cheating by teachers and administrations. Very little about the current state of education even resembles well-established information and theory about how kids learn. So much of our education system is carried over from the days when the purpose of the schools was to feed workers -- not good citizens, not people who will advance the nation and society, but workers -- into industry. That's why reading and math trump all, science and social studies suck, and arts are essentially nowhere on the map.
It's really stupid (no pun intended). And it's not going to change until we do.