I still don't see it happening, outside of silos. There's no precedent for DRM'd content outside of silos (like much of the digital publishing ecosystem, especially with ADEPT and whatever Amazon use), unlike with video and audio (through plugins like Flash).

Unlike EME, there's a far stronger argument of "the web has survived without this for 25 years" (and yes, for better or for worse, I consider a plugin with over 99% market penetration as part of the web), and I think that still holds weight.