DRM doesn’t prevent copying. There are a number of programs that crack DRM, they are just illegal. So what’s the point of DRM if it only works on people that are honest? Honest people wouldn’t make copies of their CDs for the whole world to listen to anyway.
DRM dissuades honest people from moving from an iPod to a Creative Zen. or vice versa. Dare Obasanjo discusses this in his DRM and Vendor Lock-in post.
It puzzled me why the Zune player wouldn’t support "Plays For Sure" as people would lose their music if they went from a Creative Zen to a Zune player. And then I realized. It was just baggage with no apparent benefit. Few people have DRM music at all. So they largely don’t care. What they care about is how easily they can get their CD music onto an MP3 player. And Zune does support AAC without DRM, so even if people ripped their music into AAC can play it on a Zune without having to rip it again from their CD or going through a conversion process.
Although between Zune and Real’s announcement, this is the death of Plays for Sure. It was a nice idea. But I hope in the long run it doesn’t matter. Because other than for subscription / rental models like Netflix, I don’t think DRM makes sense.