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.

When you buy property as a value store, more often than not ot's more trouble than it's worth to rent out. Not to mention that many renters, to put it mildly, don't take care of the building or the area very much, which has a big cost associated with it if you ever want to live there yourself.