I'd say that's a good possibility, for now. Consider when Apple rolled out 1080p downloads - the filesizes were only slightly larger than for the previous 720p versions, representing quite an efficiency boost. Adopting H.265 would seem to be able to chop the sizes down.

However:

- tablets and phones are unlikely to be able to take advantage of H.265 until the requisite GPU support arrives. This may hold up widespread adoption for a year or two.

- for how long will the video arena remain at 1080p? I hear Sky (UK satellite broadcasting arm of the Murdoch empire) is trying to nudge toward 4K broadcasting.