This article was relatively short but exposed an interesting trend in video game sales around the world compared to the US. Any game in the top five list is on the top five because of US sales. In other words, the top games sold are on top because of their US sales and not because they are well like by the world.
So if Americans like a game (a lot) then that game will be a top seller around the world, whether or not the rest of the world find the game to be as highly rated as we do.
What great, not so main-stream, games is the US missing by only supporting the most popular? There are thousands of games created and put on shelves yearly but only a handful reach the entire market and the rest of them are never discovered by the people that might just like them.
There are companies out there though that allow their customers to play old or not so popular games whenever they want. Companies like GameTap.com or GameFly.com; both allow you to choose any game from a very large database of games and play them (by either streaming them with GameTap or having them mailed to you with GameFly).