I think it has something to do with the better labor laws (for low-end workers) which push up prices on commodity items. I don't remember any country outside of maybe bits of Northern Europe and Switzerland where I paid more for local food. I've even been on some pretty remote islands and not paid that much, exchange rate adjusted or not. I remember the first time I paid $22 for breakfast and $5 for a smallish, very lackluster, meat pie I knew I was in for a huge hit on my wallet. I know someplace have isolated foreign or exotic foods that are expensive (the famous $11 Japanese hotdogs for example), but even in Tokyo you can find plentiful meals for under $10.
I hit a decent steak house in Canberra (Australia has great beef BTW), and was very happy it was paid for by a local. I think the tab was well over $50 a head for a steak and a couple sides.
It may have been a particularly weird time to go or something (2007), but it left an indelible impression on me.
Don't get me wrong, I'd still readily return, Australia is a lovely country for the most part.
My steak experience in the US was in Fort Stockton in Texas. A $14 steak came out, so lonely and small that it literally slid right across the plate when it was placed before me. Fort Stockton isn't doing Texas any favours for their steak reputation :)
In 2007, Australia was at the start of it's mining boom's plateau - this was when the dollar started peaking with parity with the $US, and yes, things would have been overpriced for a tourist. Curiously, during the GFC, the assumption was that Australia's economy would crumble and our dollar dropped to US60c. It made no sense, because our economy did alright while the US economy crumbled significantly. It's just a reminder that currency values are set by the gut feelings of a bunch of suits in the city, not by concrete measures.
It's a great place to live, but I have trouble recommending it as a place to visit - pretty much all the nations which produce sizeable quantities of tourists have access to the things Australia provides to tourists, but closer and cheaper. I'm not the guy the tourism board wants to hire...
We do have good steaks in the U.S., sorry about your Texas steak experience! I'd expect to pay $15 on the low end for an "ok" steak to $35 on the high end and then $3-9 for sides. Add in some beer or wine and you can hit a pretty price per head in the States. But if you just want to hit a roadhouse and get a steak an potato and a beer, I'd expect to do it for under $30.
Apparently, the volatility of the $A combined with the general stability of the economy makes it the 5th-most traded currency in the world (US$, Euro, Yen, GB pound, then $A... the middle order might be a bit mixed up)