The basic problem is that DRM is trying to keep honest people honest. With Napster out there, that's not good enough. It only takes one person to break the encryption, and then the encumbered version is competing with the unencumbered version on Napster.
This kind of technology is such a fundamental part of the Internet that to try to have a blanket ban against all technology like this is essentially saying people on the Internet can't exchange files with each other. You just can't do that.