I'm aware of that, but the crucial bit is that CDs existed (and still do for the most part) as it is pointed out in the letter. So even if it weren't for apple,

I'm aware of that, but the crucial bit is that CDs existed (and still do for the most part) as it is pointed out in the letter. So even if it weren't for apple, sooner or later things would have taken a similar turn. And that's also why this didn't extend to any other form of media.