What's uncontroversial about that? The iTunes Store did make (legal) digital music mainstream. That's not to say it was the first store of its kind, but it was certainly the first to have widespread success.
The point is trying to credit apple for "digital" music as opposed to "analog" music. That is just absurd. Credit them from making a business out of selling digital music, but not for making digital music popular.
Put another way: Anybody can tell you what a CD looks like — round, shiny, flat, about yea wide — but nobody knows what an MP3 looks like, because it is a purely digital format. The difference of physicality is the salient part here.
"CDS ARE DIGITAL MUSIC!!!"