That's one of the things being done. Problem is that for a while they didn't (that's what happens when you get people who think the market magically fixes thing

That's one of the things being done. Problem is that for a while they didn't (that's what happens when you get people who think the market magically fixes things in power) and building new ones takes time. To get that time a stop gap measure was needed, hence freezing prices for five years for existing houses, no price freeze on new houses.