The real issue in the US is going to come down to how many people can continue to afford multiple homes which is where rising interest rates and inflation both come into play. Anyone that bought a second home using an ARM may be forced into paying much more than they thought, and rising interest rates are going to put additional pressure on people with investment properties as they may need more liquidity sooner than originally expected to cover routine expenses.
The London rental market is if anything completely overheating at the moment due to lack of supply.
Agreed on the overheated market. My argument was that these properties are completely off the market and the owners won't panic-sell them
As of April 2022, only about 34k properties were classed as long term vacant in London out of around 3.7m housing units, with Southwark, Newham and Barnet at the top of the lists, largely because of redevelopment projects that meant clearing out tenants first, as well as time to get people into new developments afterwards.
<1% empty housing is not unusually high for an area experiencing a lot of renewing and new builds.