I think you're ignoring other aspects of that kind of decision-making. Yes, the feature here is "power efficient, high quality mobile video streaming", but consider that content producers have to encode, store, and serve multiple different formats (plus more licensing fees for the encoders) in order to serve all their users. That's incredibly wasteful and causes people all sorts of headaches on the backend. Both Apple's stuff and WebM do indeed satisfy the user-facing feature requirements, but Apple could have just used WebM and saved content producers a lot of time and money (which often -- but admittedly not always -- translates into saving end-customers money as well).

There's of course a balance to be maintained; if we single-source our streaming video codecs, that will dampen innovation in that space. But I'd hope there's a less wasteful middle ground than the place we're at now.