Progressively tax the shit out of each subsequent property owned. Prevent foreign/corporate ownership of property outside of short stay, hotel/motel type accommodation.
Make shelter an extremely unattractive asset to own.
Unfortunately, many politicians across the world are also landlords.
I don't think "basic need" is a good argument, as many other things are basic needs but function perfectly fine in a market-based system. This perspective sounds moral, but proposes nothing to actually resolve the problem (other than to advantage a particular section of the population at the expense of another - namely, people who would like to be homeowners). I note that most such proposals make no allowances for people who would like to rent - because they don't actually care about anyone other than themselves; they want to own a home, ideally at a low price, in a good location, with good services, on a large block.
Food is also a basic need, but does not get any of the attention because it is a functioning market.
In many places, property is not a very functional market, as suppliers (developers) are unable to respond to demand thanks to regulations/zoning.
If bread and milk were being hoarded by speculators (not some random luxury like truffles) you'd be hearing exactly the same discussion.
The point is that rich people with vested interests are stacking the deck against newcomers.
>market-based system
The free market does not exist. Property markets around the world are being heavily distorted through favourable tax treatment and speculators.
>other than to advantage a particular section of the population at the expense of another
This is business as usual, except that the advantage almost always flows the other way.
We'll see how that plays out in the coming year.
Lots of revolutions in history have been triggered by unaffordability of food, and step 1 of the classic formula for keeping people happy is food ("Bread and circuses")