It may not occur to everyone, but Netflix, Lovefilm, NOW TV or whatever don't have control over any of these things. It's entirely dictated by the movie studios, for example, we /have/ to use silverlight, because of DRM. We can't allow hdmi-out, because the movie studios won't let us. No streaming movie provider makes or has the ability to make any of these decisions, it is entirely within the realm of the rights-holder.
The only reason any of these work outside of silverlight is by the hardware vendor providing some form of DRM under which videos can be delivered. Anybody making hardware will provide this DRM if they have any sense, but for things like Linux, where DRM is a No-No and Microsoft won't support it, you're pretty much stuffed.
The irony is that the provider I work for develops the entire service on Linux, and yet any of our customers who want to watch movies on Linux, simply can't.