I don’t think this is really true. It’s naively true if you just look at the number of homeless people vs the number of empty units, but misses:
1. That markets need some portion of empty units for fluidity.
2. That many people aren’t homeless, but living in situations where they would take more housing if it was available. (Living with roommates, ex-partners, family, etc.)
3. Many places simply don’t have enough housing for everyone who wants to live there. If they did, people would move from other places.
Naively, if I knew everyone’s salaries were about to double, I’d hope to be holding a fair amount of real estate going into that doubling.
But mainly it is that you would need to remove or decrease benefits for those who do not work in order to have room for higher salaries. That is not a problem for the unemployed because higher salaries means that the only people without work are those who do not want to work. But it is a big problem for those who do not want to work and for example would like to live off their real estate.
The gut reaction to higher salaries is that people would have more money to purchase real estate or pay rent, but I think the downwards effects for real estate are much stronger. And the evidence is that in every country which has seen a period of high salaries for workers, real estate has been cheap during that period for workers to buy.
The only answer is to build more housing and have a high property tax in unoccupied housing.
You could build as much more housing as you want, but if those houses only become accessible to purchase for those who already own real estate instead of for those who work, then nothing will change.