Literally even a cursory glance at history shows your understanding to be misleading or grossly incorrect.

Ignoring the fact social housing was nearly zero until the 1930s - and that it was introduced in Australia to combat people living in slums. Even your golden era wasn’t that golden nor really an era ….

‘As the economy strengthened, the private housing market once again became a significant supplier of new housing stock. In 1956, the recently elected Liberal-Country Coalition Party leader Robert Menzies renegotiated the 1945 CSHA, sounding the death knell to the golden age of public housing in Australia. Under the new CSHA, federal money was diverted away from public housing and rental assistance schemes, states were allowed to sell public housing via any means they saw fit, and private home ownership was encouraged once more.[42] From 1956 onwards, roughly 90,000 public housing built under the CSHA were sold across Australia.[43] Further heralding the end of public housing was the emergence of economic rationalism in the 1960 and 1970s. Replacing the post-War Keynesian idea that government intervention in the housing markets was a necessary virtue, public opinion was swaying to the neoliberal idea that government intervention by the way of public housing was one of the causes of the problem.[44] This idea was helped along by the 1975 Royal Commission into Poverty that claimed that “Of the total 183,000 housing authority tenants the total poor numbered only 51,000; 132,000 housing commission rented dwellings (72%) were occupied by people with incomes more than 120% of the poverty line”.[45]’

You talk about Australia as if it’s disconnected from the global economy. Social housing is not sustainable by your own admission. We can look at the other factors for why that is now the case - but my comment was that housing isn’t the most profitable asset class. Citation please of your proof that housing investment is the most profitable asset class.

It isn’t - it underperforms a number of other asset classes. It there isn’t any incentive to build houses though then apartments etc won’t be viable to build. You can’t rewrite supply and demand unless you artificially alter it with government intervention. Which hasn’t been that successful in the past.