a doubling time of five decades is actually ne so the assumption of slow growth itself is questionable. What is interesting in the case of Australia is that it has much immigration as well as meaningful emigration. As a continent which always attracted many immigrants one should not discount the fact that at the turn from 19 to 20 century such immigration was restricted to whites only (officially abolished 1973), which might have slowed down population growth then, but you refer to the 1960s and later, when this policy had been given up. Today especially Asians immigrate in big numbers. Total numbers of immigrants are between 150 and 200,000 annually........

Looking backwards for longer Australians population has increased four-fold since WWI and more than a quarter has been born overseas...

So I guess the reasons of today population is a low starting population depopulation of the indigenous people through warfare and even more important diseases, and then an increase based on the low starting point... (1900: 3.7 million, 2016: 24 mill).

Dear Michael, there are several reasons for Australia to have small population and population density (just like Canada or Siberian part of Russia). One may say that migrants arrive to Australia only for 2 centuries, contrary to 5 centuries in the case of America. This is true, but not the only reason. Another reason is low land fertility in the major part of Australia, that cannot support too much farming.

But low population density has also negative effect on growth (in rural areas, cities are different!). There are too few people to develop a dense network of infrastructure over all territory. (By the way, this also explains low population growth in underpopulated Siberia.) Economic and population growth is only in cities, mostly in 2 largest cities - Sydney and Melbourne. You can have a look at my article: Article Socio-economic influences of population density

Many of the ethnic BLACK people of the Australia were KILLED OFF by the European emigrant to Australia. Then so called "WHITE AUSTRALIAN POLICY" rejected entrance of emigrants from other countries.

These may play a role in less population of Australia.

Because the current policy makers are racists and the cruelest ever government. They themselves are migrants and thefts who killed all true owners of that land and now they don't allow others to migrate there. They have stolen Australia from aboriginal people. What goes around comes back around.