The discussion I've talked about was in the context of an occupation of a university building standing empty for two years while many initiatives wanted the room. After 28 hours, the occupiers left because they convinced the university to let people use that space.

This might be different in the states but the city I live in is famous for building luxury housing that's used as an investment and stands empty while people sleep in the subway stations. The need for cheap housing is there, but these people have little money so the demand for expensive housing wins that might be used as second houses of the very rich or it really is empty and not used at all, just a future investment.

At some places, people will even leave houses empty to increase the market value of other houses, but that's not happening here according to the discussion.