You got a really stupid reply from the school board. These things vary greatly from state to state. Here in MA, the state contributes almost nothing to local districts (well, in comparison to other places). Per pupil cost varies anywhere between 4K and 15K per kid. I could easily see the 175K per class estimate, given salaries (yes, they are higher here. I was making 71K when I quit, with an MA plus 60). The cost of running old buildings with poor environmental systems and everything else that's crumbling adds up.
I don't know the answer to this problem, but I say run for the school board. The kids need people who are concerned, like you!