but why have they done that? are you suggesting that only "the mega rich" do this?
No, I'm suggesting everyone does this, or tries too. Everyone wants to get into property because we are very good in this country of turning any sort of boom conditions into higher house prices. If you can get into the market you don't need to do anything except live in the house and it will go up in value at a rate faster than any interest bearing investment, even if after 10 years the house is in worse condition than when you bought it. It does mean however, that people put off having children while they are in the early stages of their mortgage and need all their income to support it.
Politicians talk about cost of living pressures and fiddle around the edges with a few dollars here and there in gas and electricity prices. But the real driver of cost of living pressure is the cost of housing. To help people cope with that they keep giving more and more tax concessions, rebates, benefits and the like, rather than let the market correct itself if it has become unsustainable.
Even if it were a good thing for our long term structural competitiveness to see a fall in house prices generally, the pain felt by individuals who stand to lose would be politically damaging. Far easier just to blame the unions for everything.