The U.S. apparently gets games cheaper than most countries. We're a huge market, and our people complain bitterly every time game prices rise (seriously, look around the Escapist forums a little and you'll see what I mean.) There was an example recently about the exact same version of the exact same game from the same printer costing something like a third more in Germany.
If it's any comfort, as the U.S. continues to screw up its credit situation, we'll probably be on more or less equal footing in the next decade or so. Assuming there's still a viable video game market by then...
Um, apparently I'm a little pessimistic today. Carry on.