The on-device TV demos and Sony's 'core' 4k streaming service

>Nothing streaming at typical cable bitrates is worthy of being called "UHD," let alone "4K."

I agree! However, by that same token, 1080p streams aren't really 1080p. A not-actually-4k stream still looks dramatically better than a not-actually-1080p stream.

A lot of people, myself included, are fine with “less than optimal”. Sure, I’d prefer a blu-ray for my favorite epics, but a great home theater system also makes streaming content a satisfying and convenient experience. There’s also a lot of content one wants to watch that never makes it to blu-ray

Blu-ray is not raw, it is just HEVC with a higher bitrate. Most content encoded at a high profile level is not even going to hit the bitrate limit of a good streaming service + connection. Other than pausing during an action scene to take a still, I can’t perceive the difference.