You don't pay property tax on unrealized gains in your house. You pay it on the appraised value of your house. If you don't like that appraised value, you can appeal it (and many people do), and it often doesn't rise nearly as much as the actual value of the house.
I do pay it on the unrealized gains though! As the value of the neighborhood/property increases, the appraised value goes up and my property taxes go up. This increases my taxes based on the increasing value of a non-income-producing asset.
"An appraised value" could work for companies too! Though, in fairness, for many billionaires the gains are pretty explicit i.e. we know the public stock price or the 409a valuation.
The appraised value is rarely very tightly linked to the actual value of the house. It gets adjusted once in a while, and if it's too high you can bring it down, but otherwise the appraisal tends to adjust with inflation while the house price tends to float relative to it.
I just don't understand how this has anything to do with the wealth tax. It's not an argument against a wealth tax, it's an argument in favor of a specific implementation: what value we're using to calculate the tax.
> It gets adjusted once in a while
It gets adjusted nearly every year for most people.
> if it's too high you can bring it down
No, you can't. Not really.
Personally, my property taxes are about 2.25% on a appraised value that is about 70% of the actual home value. This sounds great, let's use these numbers for a wealth tax.
> It gets adjusted nearly every year for most people.
For inflation, yes. Real re-valuations that mark the house to market are a lot more rare, and tend to only happen when a house is sold.
> No, you can't. Not really.
I have personally done this a couple of times, and all it tends to take is a nice letter explaining why the value is too high. At worst you need to get a new appraisal to support the letter. The value is rarely too high, though.
Property taxes in my area are also relative: the tax rate floats depending on how much the local government needs to raise. The sum of the appraisals for the city is added up, and your property tax is your proportional share of the total amount that needs to be raised. For me, that's usually around 1-1.5%.
This is all to say that property tax is not at all a tax on unrealized gains of your house. It's a tax on an imaginary number that occasionally adjusts to be similar to your unrealized gains, and often even has a rate that floats relative to it.
