For many people, the primary goal isn't lower house prices overall, but a change in approach to how we approach housing (especially zoning) in order to make shelter affordable.
It's not that everyone wants McMansions for cheap, but rather they want to see things built that are reasonable in size and affordable for normal workers. This could be anything from large concrete block apartments (they can be made cozy and nice!) to tiny house villages.
There are many great ways to live which are literally illegal to build in the USA due to archaic and regressive zoning laws, minimum parking requirements, etc.
https://www.youtube.com/watch?v=CCOdQsZa15o