Tim Bray puts his finger on why DRM will fail, and, hey, he works for Sun:

What all the DRM dreamers don't want to admit is that 95% or more of the population hasn't yet encountered DRM, and when they do, they aren't going to like it. They're going to scream and scream and scream and get mad as hell and not take it any more. As much as I complain about DRM here this is why I know (or at least hope) it will fail. My advice is to keep screaming.