The article headline is correct, but the explanation given in the article is incorrect. Our frame of reference for the successor to the iPod won't be the iPod itself because, like the Walkman, it will be completely different from its predecessor.
I wonder, though: what else is there to do? After you can fit your entire music library onto an iPod, and navigate it incredibly easy, what's left to add on? Beyond new features, like the iPhone's doing, and - eventually, once there's enough space - lossless audio formats.