A house will only sell for 400k if someone buys it for that much. That’s the demand part. Building it isn’t what made it sell for 400k. Then the house next door that’s not removated yeah now they know with up to date renovations they could sell close to that. But the house next door selling for that didn’t raise the prices for everyone. It was jus price discovery. (Putting aside if the house took up the place of an empty lot or blighted property.)