I agree that more legitimate sources for media in a form that the consumer wants will undercut piracy. I also believe that the value of DRM is questionable in reducing piracy (and may even encourage it when it restricts consumer's access to legitimate sources).
Still, I had the urge to play with the numbers on PC gaming. If you subtract China from the equation, worldwide growth was closer to 7.5%. Still good, IMHO, but it is a good demonstration of how one market can completely alter the figures.