There's actually an HTML5 "DRM" API being proposed right now by Google, Microsoft, and Netflix. I don't really know the details, but the idea is that they want to make it possible to encrypted video/audio streaming. Incidentally, this type of feature is primarily why a lot of other sites that stream copyrighted content (e.g. Pandora, Rdio) are also "stuck" on Flash.
There are a lot of open questions about whether or not the proposal will be accepted by the web standards community (as you might imagine there's a lot of resistance), but it seems like this could be the death knell of Flash.