Well because the property is extremely overpriced when you consider market rate rents the yields are extremely low. You can only charge as much rent as the market will bear, which in some ways makes rental completely different to ownership prices.

Basically the people buying it don't deam the return on renting it worth the risk of a bad tenant or worth the hassle.

They don't need cashflow, are either using it as a safe holding of value or as a quick escape property if they need to leave insert country here for political reasons.

It's happening the world over.