"In most places in the US, the amount paid to schools has gone up far faster than inflation over the past several decades, while the schools have produced no significant improvement in educational proficiency with the extra funding"

This. When I graduated high school (about 15 years ago) the amount spent per student was around $5k a year. The high school was in the top 1-2% of public schools nationwide. The school now spends around $14k per student and is in the top 15-20%. What changed? The perception of the school. The parents whose children would pull that number up have chosen neighboring school districts (myself included).

The urban schools actually get the most per student in the state. $14k-$15k from the district alone, with additional state funding pushing that number north of $20k (some schools reaching $25k). There is not a funding issue at all. They have the lowest student to teacher ratios in the state, along with the most teacher aides and social workers.

And this isn't on the coasts, this is in the upper midwest, so the cost of living is not high.