As an Australian... I have no idea where this idea comes from. American Exceptionalism has historically been a thing, but other than a general impression that equipment which have been designed and built locally in Australia tend to be above average assuming that it wasn’t built to be the cheapest... the idea that “our stuff is the best” has never really been a thing, except maybe Beer... and only among people who are obviously fans of that beer.

Edit: This might be an east coast vs west coast of Australia thing. I’m from Western Australia and I just realised that this might be more of an east coast cultural thing...