In an echo of what derekp7 said above about the music industry turning to no-DRM as a way around Apple's restrictions on the iPhone, there are publishers who are turning to DRM-free sales of books directly to consumers to bypass Amazon's control of the Kindle ecosystem. O'Reilly and Packt come to mind immediately, but I'm not sure if it's a function of their audience or I just know of them because I'm in their audience.

EDIT: Which, to the larger point -- DRM is two things, a content play and a platform play. Standardizing DRM is one way to limit the power of platform holders over content providers. Eliminating DRM is another. Deciding whether standardizing DRM is a lesser evil than leaving DRM up to platform holders is a question of who do you fear more, the content owners or the platform owners.

Hmmm, good point. Perhaps it's a partial explainer, and other factors like inertia, popularity, reach, etc. need to be factored.