Most companies are playing off the fact that Australian customers are usedto paying X amount of mark up, completely independent of the actual dollar value. So why bother changing it? Pocket the difference, and most people are none the wiser.
Apple very rarely changes the price of a product once it has been released. And the initial splash price of the product is calculated with exchange rates prior to its launch. Great if the Aus dollar is strong, and SOTL if it's not.
It's a pretty lame position to be in, but there you go.