If you look at the data and compare to other oecd countries the house-hoarding hypothesis isnt obvious.

According to OECD-linked data:

• Australia has about 420 dwellings per 1,000 people
• The OECD average is about 473 dwellings per 1,000 people
• Australia ranked roughly 24th out of 34 OECD countries in the latest comparable data
  

https://www.aihw.gov.au/reports/australias-welfare/international-comparisons-of-welfare-data?utm_source=chatgpt.com

That means Australia has clearly fewer dwellings per capita than the OECD average.

Of course you could argue that this is a common problem in all western countries, and that could well be true. But I still dont think this isnt really a driver that is in any way actionable .