It's actually not that surprising, considering the subject matter is cars, and particularly car racing. NASCAR is the most-watched sport in America...even moreso than the NFL. So basically Pixar managed to create a franchise based off of America's most popular sport, and in an area that's a virtual untapped wealth in terms of audience: the "flyover states."

And while it's their weakest story, it's still a good story. It's ironic, but not surprising. XD