RE "problem is caused by a lack of building" In my opinion there needs to be more houses built so the vacancy rate rises from the present extremely low ( round 1%) to the long term average of around 3% house vacancy rate. This 3% vacancy rate is recognized as a fair equilibrium between renters and property owners. Furthermore such a rate helps stop property owners raising rents as much , as happened in recent years. This is in Australia, do not know about other countries. Alos with record low interest rates, my opinion is lots people over commixed to loans, without proper consideration if they could afford the loan when interest rates rise to the long term average of around 7%