zlacker

I agree that some property is left empty, but this is extremely rare. There are just not enough lazy Billionaires that can afford this. In most cases empty means unable to sell or rent out. You'll notice that most developments in London these days (e.g. [1]) are mostly small studios, 1 or 2 bedrooms. That's because large luxury penthouses are hard to sell, there is little demand.

Most buyers of such property (whether private or investment funds like Deka-Immobilien or BlackRock Global Property or Brookfield Property Partner or one of the many others) do this as an investment vehicle with a particular risk/reward structure. They will absolutely have to rent out these properties, and indeed, when they fund property construction projects, as they have been on a massive scale in London in the last decade, they do so to cash in on rent.

[1] http://www.themadison.co.uk

>>mafrib+(OP)
Yes, the billionaires get a lot of blame but in terms of numbers, they are insignificant.

I would imagine that a much bigger issue is old people who are in a care home or a hospital, unable to live in their old place, but not willing/able to give it away either.

At least over here (Finland) this is the major reason for "empty" apartments in central areas of cities.