fronzelneekburm: Russia: $16.99/$19.99 This gets me thinking...
People who defend regional pricing always bring the argument of how flat pricing is unfair to countries with a low average income. Now, I don't know the first thing about the Russian economy. But I'm willing to bet that the average Russian income - no matter how bad it is - might still be better than, say, most of the African countries that are quite negatively affected by regional pricing.
What I do know is that Russia is notorious for widespread piracy and that the only thing that allows a legit distributor (such as gog) to even set its foot on a market flooded with cheap bootlegs is to make their software available with a low pricetag.
The conclusion I draw from this is pretty depressing: If Europeans and Australians (or Africans, for that matter) don't want to be screwed over by regional pricing, piracy needs to become as rampant in their territories as it is in Russia.
That's true for other countries as well. I live in Lithuania and calling piracy rampant would be soft. More like it's the standard. The reason is exactly the same as you stated - difference in income.
This is actually a topic I've researched before. Taking purchasing power parity per capita into account, a game costs a Lithuanian anywhere from 1.5 to 2.6 times more than some Western European countries. The price itself is the same, yes, but due to our lower income, it's value is higher for us.
So when a game is offered at 55$ - the same as our richer European counterparts, it's costing us a lot. No average person can shell out that kind of money for a game. Using the factors I mentioned earlier, it would be like someone from Ireland paying 104$ for their game (a factor of 1.9). I doubt you'd find many Irish folks paying that much for a video game.
Now 17$ like in Russia? That's a whole different story. 17$ for a pre-order like this is very acceptable. I assume this is exactly the reason the prices are so much lower there. Now what I don't know is why it's only a practice in Russia. Probably something to do with EU's laws or policies. And, like it was said here before, having a very populous market doesn't hurt too.