We've been down this road before.
Local prices depend on local business conditions: taxes, wages, rent, utilities, sales volume...
If they are being sold by aussie subsidiaries then the price will be a function of the cost of running that operation, which often is a function of the *size* of the market. As Harry pointed out, a digital content operation will only be able to sell content from the publisher licensed for that region at local prices.
If the local publisher charges Apple or Amazon or Kobo higher than US prices (which might be because *they* have higher costs) the retailers can't be expected to eat those higher costs just because a politician says so.
Not sure how high the overall business costs are in the antipodes but I doubt they are as low as in the US. If nothing else, the minimum wage down under is twice the US minimum. And I doubt that is an aberration. Not when Sydney is the fifth most expensive city to live in in the world.
http://www.independent.co.uk/news/wo...n-9167514.html
So if you combine higher local wages with smaller market size (driving up the per unit license cost) then a higher price might be inevitable.
There is a lot more going on than just wanting to rip off customers for the hell of it. You may be looking at a chicken-and-egg scenario. The law of unintended consequences works in mysterious and often annoying ways but it can't be legislated away any more than the speed of light can.