So long as digital copies such as UV come with end-user agreements, I don't see the demand for discs going away. If you'll read the fine print on a digital copy, you'll see that you don't actually own anything: Your title can be pulled the moment the studio decides it doesn't want to keep making it available. No one's bound to knock on your door demanding a disc. And sharing a disc is as easy as saying, "Here ya go."
I will give up my Physical Media when the morons of the world have embraced digital to the point where I can no longer purchase physical media. Physical Media does not require the use of 100+MB/s broadband & is not compressed to the point of looking like cruddy to a videophile such as myself. I guess I can thank the greedy American ISP's & their failure to give fats broadband everywhere for the survival of physical media.
"Although videophiles have been predicting the eventual death of physical media..."
No, videophiles recognize that physical media provides the best picture quality, so have been the ones supporting physical media like Blu-ray. The anti-disc soothsayers are people who don't know doodie about video, like investment advisers..
UHD has 4 times the data than 1080p--more when you start adding a wider color gamut and higher frame rate--yet they only doubled disc capacity. I know the newer codecs do a better job of compression, but I can't help but think this new format may come up short.