>This could be extended to the ephemeral nature of digital formats and their co-dependence on certain execution environments.

there is significant difference - knowing the format (or even just basic principles of the format like in case of compression) one can restore the content ( http://www.cs.huji.ac.il/~springer/DigitalNeedle/ ), while in DRM case knowing format isn't enough. Another illustration - one can apply some analysis and probably read lost ancient language texts while it is fundamentally different from reading cyphertext even in known language. I.e. DRM is intentionally and explicitly converts "information" into highest entropy content, i.e. "erases" the "information". Basically what flame does to human artifacts.