It doesn't matter how many houses remain empty in the US as a whole. Presumably locations with high vacancy rates are places with low demand (ignoring, for the moment, places with large amounts of foreign real estate investors who parasitically decide to leave their properties empty).

Raising wages in places where housing is in high demand, but short supply, will just serve to increase home prices further. That doesn't mean we shouldn't raise wages, it just means the real problem housing-wise is the lack of supply.