Arguably the original iPod fits in alongside the original iPhone and Watch. It was significantly less of a finished, polished product than the commercially successful 3/4th gen models onward that people tend to think of when iPods are mentioned.
Only because the connected market is many times larger did it sell better. It's not fit for purpose and the audience will take a decade or more to reach numbers that make it worth it for app developers and even then it'll be a dorkbox for your face and not used much at all by the "productivity" half of the office that care about hair and makeup.