I've read it and I agree that the visible changes may be evolutionary, but the packaging, ease-of-use, and DRM changes are rather large.
I was amused to see some of the rhetoric used when discussing how Jobs didn't "note [the] debt [Apple] owes to those services and to the defunct music companies that came before them." It seems that the author is somehow expecting that technologies pop out of thin air. I certainly don't remember many complaints about this during the much-hyped Internet era when every incremental improvement was called a "revolution".
Be that as it may, Apple has always gone for incremental improvement, but in leaps. They didn't change just the DRM or the ease of use, or the OS integration, or the subscription model, they changed all of them at the same time. It's like claiming that the Ray Kroc wasn't an innovator because people had served food quickly before and had franchised ideas before.
The proof will be in the pudding. Apple may or may not become the largest music retailer on the planet, but there will be little doubt a year from now that what has been made available in this service will be pushing others to continue to innovate, and that's Apple's greatest attribute.
Don't forget that Apple's incremental improvements in MP3 players resulted in the world best selling line of MP3 products.