"... may have bought its success"
With the iPod being a consumer product, Apple needs to advertise it, as do ALL the companies that sell consumer products. Therefore, I find the comment that Apple "may have bought its success" rather strange.
Don't forget that Apple actually makes a profit out of every iPod sold, unlike for instance the game consoles. Sinking billions of dollars subsidizing each console to achieve maket share (or dominance), that's what I would call "Buying success".
Might it not be that, other than being heavily advertised, the product might also be attractive to the buyers? If advertising alone would make a poor product a hit, then the Zune should be a raging success