I think it often depends on big resellers (like Best Buy, for example). They can provide discounts which Apple will not do directly to the customer, and which other resellers can't do because they don't turn enough units.
That's true of many other common goods worldwide. Unless you can buy a locally made item in a lower purchasing power country, you will usually pay a currency exchange equivalent price for the item. Actually you often pay more because the local shop selling the product cannot get bulk pricing and pass along the discount to you.
Finally, when you add the local taxes - 23% in Portugal, for example - the price can be much higher compared to Alaska, US (< 2%). That last bit is really not Apple's fault.