There should be a law (in a city, or state, etc) that says housing costs should be a fixed percentage of income -- and outline the measures needed to make that happen, in terms of actual policy requirements. As part of that, if the right policies fail to be enacted, courts should be empowered to enforce them.

In other words, legislatures should require themselves to fix the problem of high housing costs, and if they're not capable, the courts should be empowered to solve the issue by cutting through red tape, issuing fines, etc.