Coming back to the headline and leaving the Aussies for a moment on the side.
For more than 15 years I am doing 145/135/91 audits, all over the world. You find on each continent good ones and some, which you know after the audit, never fly with them.
But, subjective from my experience, the standard in the USA is definitely lower as in most Europe and several countries in Asia / Oceania.
It is unacceptable for a lot of countries to allow airlines to continue flying after finding major maintenance discrepancies just with a "financial penalty". We you drive too bad or drunken, you loose your licence. The same should apply, as a minimum, for aviation in all respects.
And to all who question the safety record of Quantas: Just go their and look on the maintenance they operate. Not perfect, but far exceeeding the most done in 121's in USA.