> From OP's calculation, a great school may cause at least $200K price increase per house
Say it with me: Correlation does not imply causation!
Correlation does not imply causation!
Correlation does not imply causation!
Correlation does not imply causation!
(And schools in the U.S. are funded largely by local property taxes. Therefore, the arrow of causation might very well go the opposite direction here: the places where homes are sold at higher prices are assessed at correspondingly higher taxes, and therefore those school districts get more money, and thus perhaps -- perhaps! Correlation does not imply causation! -- those more heavily funded schools are regarded as "better".)