Well, the other issue is our cost of living as a whole is just higher than the USA. Google the "average salary for USA" and then the same for Australia and you'll see what I mean. Just where our currencies work out to, and where the oil comes from (and which currencies are used) that probably count.
Add in the fact that we are no longer self-sufficient for fuel, and hey presto.
The way I see it, Ford and Holden (in particular) have been having issues for a long time. They have relied on the government protecting their industry with ridiculously huge tariffs, getting handouts and just hoping that the "average Ford/Holden family" is going to keep buying.
The thing is, I think Holden/Ford left it too late with introducing a feasible medium-sized car like the Camry, which had the option of a I4 or V6 (the latter actually making the Camry a "large car" by Australian standards).
Still, they're both interested in pushing large sedans like the Commodore (with V6 or V8 engines straight from Chevrolent/Buick) and the Falcon (I6), neither of which are particularly frugal in comparison to the competition, more so historically.
Coupled with rising fuel costs, increasingly tight city parking and better competition (which was often built quite a lot better and didn't nickel and dime the owner for its lifespan), have resulted in these two leaving the Australian market.
While I feel sorry for everyone that lost their jobs (including at Mitsubishi and Toyota, too), I have to say "Serves you right" to Holden and Ford. Build what the people want to buy, not what you want to keep building for 'historical value,' and rely on the government to save your behinds. Thats not business, its laziness.
The European manufacturers, despite costing a fortune due to their luxury-orientation, are still largely assembled and partly manufactured in Germany and other countries. These markers have diversified their products from the zippy, no-frills vehicles, right up to the fully-loaded, top-of-the-range, fuel-guzzling sedans some people want. Business is booming. There is no reason we couldn't do that too, except the market locally was a no-frills fuel-guzzler, or an "even bigger" fuel guzzler with all the modcons.