The table in the article seems to contradict its own headline.

The headline says there are not 40k vacant homes, but the table breaks down the reasons for vacancy of just a bit over 40k homes. So it sounds to me like there are in fact 40k vacant homes.

And it goes on to say:

> Yes, 40,458 units of housing in San Francisco were classified as “vacant” in the U.S. Census Bureau’s American Community Survey (ACS) for 2019.

However it also says:

> an occupied unit is actually classified as “vacant” for the purposes of the ACS if the person living in the unit is planning to move within two months of being surveyed

But this doesn't appear to match any of the categories that sum to 40458, so I am not sure if this is even applicable.

> When a good's supply is constrained, it becomes a store of value. See: gold.

That doesn't make sense as stated, because every physical commodity is supply-constrained to some extent, even and especially the ones that are extremely bad stores of value. Picking on Fermium (it has a nice atomic number) - Fermium is supply constrained and it makes a horrible store of value because it rapidly morphs into something else.

Gold is a well-liked store of value because it is absurdly stable (about as close as we can practically get to indestructible) and roughly the easiest to physically store out of all the durable candidates.

When property taxes are higher housing is built more densely.

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.