So yes, the rich do leave I think more places empty in some places because they can afford to and because the economic calculation is not simple. If you rent and want to end the rental later you end up in a bad spot.
Ok, this is a nice story that one could make up. But once again, my point is that vacancy rate is something that is already tracked.
In San Francisco, the vacancy rate is about 3.5%.
So, in other words, regardless of whatever story you are making up about parents, or rent control or whatever, the actual data shows, that the vacancy rate is very low, and therefore not much of a problem.
I know someone who sublet an extra room to someone, a year later her wonderful lease was destroyed, landlord sued her and the women never paid a dime, could not be evicted, claimed she felt unsafe and got a restraining order against the person actually paying rent etc so they ended paying rent on two places, one to live in and one for the women.
I mean - this stuff does turn you off renting a small bit.
That said, supply is REDICULOUSLY constrained around here, red tape is nuts, minimum requirements crazy, affordability payments high etc. So yeah, no question that there is artificial scarcity.
Fortunately, this is already a metric that is tracked, called the vacancy rate. And what we see is, that in in-demand cities, that have high rents, the vacancy rate is pretty low.
So, if the vacancy rate is 5%, that means that if you build 100 houses, then 95 of them are going to be lived in. Yes, it sucks that those other 5 houses are not lived in, but those extra 95 houses, in our example, are still a good thing.
> This is precisely what happens in places like London
It is really not. A quick google search shows that the vacancy rate is as low as any other major in-demand city.