Those mostly British-descended Australians were largely sent to Australia involuntarily as a court sentence. It was a penal colony. This explains a certain amount of aggressive ingenuity and willingness to flout the rules, which makes Australians the only people who are as a group somewhat like Americans as a group. This, despite the fact that of the original British colonies only Georgia was a penal colony.
That’s true, and a good point that it wasn’t only the supposed “best and brightest”, voluntarily adventurous Europeans, who were able to create civilisation in a harsh environment. The ancestors of contemporary Australians were the criminals (though it wasn’t hard to become a criminal when stealing a loaf of bread was a hanging offense), who were exiled to Australia, and still created a thrivng civilisation in a very harsh environment, with dangers completely new to them (highly venomous animals, harsh environment and climate, etc).
Whether you came to the US because you were sentenced here, or voluntarily, once you arrived you were in an environment where you either got tough and displayed ingenuity, or you died. I would imagine it was a similar deal with Australia.