One obvious solution would be for Australia to start or join a free trade zone. In the European Union you are not allowed to prevent people from trading across borders or discriminating them on their country of residence, so price differences between countries are relatively small.
I realize most free trade zones are between neighbouring countries but I don't see why they couldn't do a free trade zone with the USA, for example.
New Zealand has one with China, and a bunch of other countries. We also have almost no other import barriers, grey market imports are legal and we can even easily import and register second hand cars, impossible in most countries.
People always find a way... Never looked at Adobe, but, Cisco, Apple, Microsoft and more all have reseller programs that have agreements that only allow you to purchase from your own country or there are penalties/no rebates/no support/similar if you go outside - along with other rules such as making distributors only sell to partners.
I'm not saying it isn't possible - I buy a lot of kit from mainland Europe where it is cheaper, but, this basically locks me out of the Cisco partner program where I would be a gold partner by now with many other benefits...
I realize most free trade zones are between neighbouring countries but I don't see why they couldn't do a free trade zone with the USA, for example.