Because development and permitting fees aren’t the problem. People already want to build new homes. We just don’t allow them to do so.
In fact, those subsidies are often part of the problem. The only way to get new development approved in many cases is to include a number of below-market units in the development… even though they are subsidized, that mandate kills the economics of the project. It happens often enough that you start to wonder if maybe that isn’t the point.
Well whatever. Hand vacancy taxes to developers as straight cash incentives to build more. Bonus per unit completed or any other metric that isn't subject to gaming. The point is, make it cheaper to build.