Well its either that or flash...think I would rather HTML5.
You think the DRM blob would be less slow, less buggy, less closed and less resource-hungry than flash is and has been? Think again.
In that case, a browser implementation could just write the unencrypted video to disk or re-stream it over http to other clients, without even having to do a new transcoding/compression (which costs cpu power and reduces quality).
The whole point of effective software video DRM is that the plugin must render the video to screen itself, and ideally in a way that doesn't let the attacker find the unencrypted stream in memory. Silverlight does this via PlayReady for example.