Total spending per pupil has doubled since 1980 and quadrupled since 1960. Both total spending and instructional spending have increased by a third since 1990. . . . A per-pupil difference of $1,200 between poor and rich schools is small potatoes compared to the average increase of $7,000 across all schools since 1980.Our schools do worse than those in some other countries, but not because we spend less money; we are second in the world in per pupil spending after oil-rich Norway.
As to why we do worse, I think the answer is pretty simple: because we care less. We just don't value education in America like many other countries do.