You have obviously spent time in Amsterdam also because you my friend are on drugs. This has been going on well before the strength of the Aussie dollar hence why it was excepted in the past. Now with the strength of that dollar and the majority of developers been those outside Australia should it not be cheaper?
You are confusing two prices.
One is the price of an item in Australian Dollars which you pay.
The other is the price of an item that you buy, converted to US$.
If Apple's cost for a computer is say 80% in US dollars, and 20% in Australian dollars (employment cost and other cost incurred in Australia), then with a stronger Australian dollar, what you pay in Australian dollars should go down significantly; the price converted to US$ should go up slightly because Apple's Australian part of the cost has gone up.
And that is _exactly_ what is happening for Apple's hardware: The cost converted to US$ is slightly higher than in the USA, reflecting the fact that salaries, cost of offices and stores etc. has gone up for Apple (plus the additional cost of better consumer protection in Australia). The cost of the hardware in Australian dollars is actually going down.
If you go to a hairdresser, whose cost is 100% in Australia, the cost of a haircut in Aus$ should stay unchanged, but the cost when converted to US$ will go up, as the Australian Dollar gets stronger. Strange enough, that doesn't get mentioned.
We do have several local online retailers which cater for other devices but the big problem is if you have an iPhone/iPad/iPod you're locked into iTunes for your legal downloaded music. No one in the world has the legal option to use other online services. Your only other legal choice is to go and buy the CD and rip them into iTunes, assuming your new Mac has a DVD drive.
Who says you are limited to iTunes? I buy music from Amazon, I have actually bought music directly from a record company (Deutsche Grammophon with a huge selection of classical music, Naxos does the same); I could download audiobooks from Audible, but use another company which is not in my own country and got lots of free audiobooks from librivox.com. It is really clueless to claim that you are in any way locked into iTunes.
In NZ it's legal to use iTunes US (it's considered a parallel import which is completely legal); it would surprise me if Australian law is significantly different.
That's an interesting question. There's also the question: What is legal for you, and what is legal for Apple? Apple will have a contract with the record company, and that contract may only allow them to sell music from the US store to US customers. I think in the EU, they must allow anyone in the EU to buy from any store in the EU (but record companies would still try to force limitations onto Apple).
I'm quite sure it's legal for you to buy the music anywhere, but Apple might not sell it and might not be allowed (by contract) to sell it to you. And their terms of service might say that you haven't actually legally bought the music if you purchased from another country, so you might have the music on your hard drive, and you might have paid money for it, but it might still not legally be yours.