AFAICT, people weren't talking about the success of the iPod until 2004, and a bunch of people showing sales figures and historical analysis concur with that: the iPod was even described as "a flop" until the calendar year following the release of the iTunes Music Store. Of course, that also might not be causative: it was only in 2003 that they caved on supporting USB, and in 2004 they came out with the mini.