Minor nitpick, but ripping from CD to iTunes in the early days was a nontrivial process for the technically challenged. I'd argue that audiophiles were the group most likely to have done this, i.e., to get lossless music files. (The resulting file sizes were monstrous, of course, and this eventually led to some storage issues. But I digress.)

I'd argue that the technically challenged were the vanguard of buying music files on iTunes. The tech-savvy were torrenting, and everyone else found the iTunes store a really easy way to click and download music. In fact, I distinctly remember snarky comments back in the day about how paying $0.99 per track on iTunes was "a tax on technical illiteracy."