Its all to do with supply and demand. Game developers and console manufacturers often dont have the resources to release a game or console worldwide all at once - also it enables them to test whether a game will be a success by testing it on a region first, or a catastrophic loss may occur, allowing the company to make strategic decisions on how many to release for other regions - if at all. The "home" market is Japan and asia. the second biggest is america. the short straw goes to europe, with its mixed culture, varying levels of GNP and of course the language differences, making Europe much more difficult to market than the more straight forward markets of America and Asia
Understanding why just makes it more painful
It sucks rock