Partly, selling into another country is a bit of a headache. That's one reason why US businesses can do so well - they only need to succeed in a single jurisdiction and they'll make a lot of money. Yes, there's different state laws, but pretty much all countries have annoying state laws, and not all countries are as lucrative a market as California alone.
I get the impression that state laws are significantly more uniform in Australia than the US... IMHO, it's more that distributors are "used to" a lower AUD, have exclusivity/best price guarantees, and so can prevent anyone importing goods (at retail scale) that undercuts them. They've got their business model worked out on the basis of higher prices, their customers are used to higher prices, and they make arguments like "hey, well, we ran a bit of an advertising campaign and submitted your product for regulatory approval". Perhaps true, but not necessarily worth the extra "tax". See the story about how the digital price for Australian buyers of The Witcher 2 got increased because the Australian distributor made a fuss: http://www.kotaku.com.au/2011/05/why-does-the-witcher-2-cost...
There's certainly that factor, but then it even happens with the app store. Though what I think happened is that the distributors kicked up a fuss when the iTunes store was made available in Australia, so the record companies made the prices higher. Apple learnt from this experience that they could make the prices higher, so they've replicated it across the board. I guess there's also the possibility that some larger app store developers have been able to convince Apple to make the price differential higher for Australia as well.
Theoretically, but setting up a business in Greece doesn't get you the same degree of market access to the EU as setting up a business in New Mexico gets you to the US.
You still have to deal with a lot of very different sovereign states, languages and mentalities. A Swedish customer is not going to feel much different about dealing with Greek business than dealing with a Russian one.
Imagine you want to start a business selling your own brand of briefcases. In the US, you can set yourself up to supply to the whole US (almost) as easily as you can to deal with your local state. Try organizing shipping, sales taxes, customer service etc. for all Europe and you'll probably decide to start with one or two countries.
As a citizen of a country in the EU, I certainly feel different about dealing with a Greek business than a Russian one. For one, I know they are required to provide me with a two year warranty by law. Likewise, there are other community directives that I know Greece was required to implement and that apply to them.
I also feel more confident about my ability to influence consumer protection entities in case something goes wrong, 'though I'm not sure if that's actually true.
Consumer protection laws are independent of the country where stuff is made or where the manufacturer legally resides. Every company selling to EU consumers must abide by them. For examples, google the complaints about Apple using "4G" in their iPad marketing materials, or discussions about the usefulness of AppleCare (most of what it promises you already is a consumer right)
hehe, except that Greece might not be under those obligations for long...
In general though I agree, (from the UK) I'm happy to buy stuff from EU places; I got my Das Keyboard and a Samsung phone (Galaxy Note, useless, sold on ebay) from Germany because it was cheaper (actually, it's also seemingly impossible to buy the Das anywhere in the UK.)
I also happily buy from the US and Canada though, as they make the funniest T-shirts, and the price ends up similar to custom printed in the UK even after import tax (not the £1.50 tax on a $20 t-shirt, but the £8 royal mail stick on any parcel with tax to pay), because of the exchange rate.
Partly, selling into another country is a bit of a headache. That's one reason why US businesses can do so well - they only need to succeed in a single jurisdiction and they'll make a lot of money. Yes, there's different state laws, but pretty much all countries have annoying state laws, and not all countries are as lucrative a market as California alone.