> Some portion of the population wants to see house prices continue to increase and they will vote for politicians who will implement policies which will support that agenda.
It all comes down to one simple problem. Housing is both investment AND acquiring housing is basic survival necessity.
As long as both are true, the problem will persist.
Imagine a world where rich individuals and investment bankers would decide they have too much cash and want to use it to buy out all food. They calculated this will drive food prices up and they could sell it with a profit. They bought it all and now they sit on piles of food that are increasing in price while majority of the population is slowly dying of starvation.
What's more, at some point some will start selling it and the food prices will suddenly go down and they will ask the government to somehow make sure the prices stay high. They already got used to the fact the prices of food will be exorbitant. Maybe they bought it when it was already high? Or maybe they took a loan to buy that mountain of food but the loan is contingent on the price of the food being high.
All the while people keep starving.
Ridiculous, and yet this is what is happening to housing.
There are as far as I know only two basic angles to solve this problem:
1) Make so that houses are no longer investments or at least not the best investment out there.
2) Make so that acquiring housing is no longer necessary for survival.
The problem is as you said -- majority of the population who have invested in a property and now think it is more important for them personally to benefit from increasing prices than solve one of the more important problems for the society.