Earlier quoted context omitted.
Some 10-15% of San Francisco housing is unoccupied. The exact why and how to fix it are arguable, but I'm doubtful the investment is actually helping. https://www.pacificresearch.org/time-to-ask-why-so-many-san-...
When a good's supply is constrained, it becomes a store of value. See: gold. Strangely enough, if housing got built in response to price increases, there would likely be less unused housing, because it would be seen less as a way to store capital.
This is because the store of value quickly becomes a millstone around the owner's neck if it isnt being used efficiently. That's a feature if you want a healthy city and a bug if you're one of the ultra wealthy.
The UK is a bit like San Francisco in this respect. There are no property taxes, just something called a council tax (which is basically a poll tax) and "stamp duty" which is levied only on property transactions.
The latter is particularly toxic because it actively encourages property hoarding.
This is why London is an alpha world+ city which can't build up to save its life.