I'm not sure I feel that way. They don't have to purposely mess up their stories to please other countries, but if they're only going to do stuff which is suited to an American mileu, than that is going to affect their repuation as creating "timeless" and "universal" stories.So in other words, Pixar didn't let foreign box office considerations effect their storytelling. Once again, something refreshing from a movie studio.
Usually, this isn't that big of a problem, since there are plenty of animated films where pop-culture gags are dubbed and altered for other countries. But with a film like Cars, it's all about the Cars, nothing else.