> Building physical houses to sit empty as a financial instrument has to be one of the peaks of capitalist insanity.
I quite agree, and I am therefore very suspicious that this is actually happening in significant volume! I have never seen convincing evidence that this happens, and it, at least superficially, makes no sense as a money-making scheme (Worried about degradation? That just means you should get insurance.) In general, it doesn't make financial sense to keep capital idle, and claims of such should be taken with a grain of salt, especially if the messaging is politically charged as "rich foreigners are screwing the common man over to make money".
I agree that an LVT would be the solution if this were actually a problem. And that an LVT solves many other problems unrelated to evil foreign billionaires.