I have no strong opinion on the original thesis but your fact doesn't make the point you think it does; you're right that no one lives in most of Australia, nearly everyone is concentrated together on the coast. Australia is a bit more urban than the USA overall from a population perspective, despite being vastly less dense overall due to the areas that no one lives in. So there would be fewer people to carry the cultural individualism.

https://www.reddit.com/r/geography/comments/1nbrov9/australi...