This scheme basically just creates a special class of plugins; these plugins clearly won't be OS-agnostic, because they can't -- that's the whole point of the exercise: to restrict playback to devices that are fully authorised/controlled from top to bottom, with the browser piping streams from the web to trusted plugins running on trusted OSes using trusted hardware (TPM etc).
If I want to watch netflix or play GTA5 on my haiku box I'm SOL as it is unless there is a business case to be made for doing the port.
This actually makes things easier. For example netflix currently uses silverlight for their streaming, this means that in order to watch netflix you need something that supports the entire silverlight stack.
With this proposal all you need is modern browser and a compatible CDM which is a much smaller chunk of code.
Technically speaking it's almost the same as the status quo, but a little bit of DRM principles have now been enshrined in the foundations of our web. Depending on what your view of DRM is, of course, this is good news or bad news; but from a technical point of view, it changes very, very little.
That's exactly the point, the case is NOT so with HTML and JavaScript. A webapp I write in HTML and JavaScript is OS agnostic!
