I have doubts that 4K content will even be common in less than 10 years. I never see 8K catching on, even 4K is at the edge of what the human eye can see in terms of detail. The premise of 8K assumes that everyone in the future will be watching TV on 120" sets. My feeling is that the 55-65" market is what the general public is satisfied with given the typical room size and that's not going to change in our life times. 8K, 16K whatever, it just makes for a great Demo but just because you can do a thing does not mean the public is interested in paying for it. Ask your wife if she cares if a show is in 1080P or SD, you might be surprised at the answer. My wife really does not care! I showed her some top class 4K sample files 560MB for 90 seconds of video and she said yes that's nice but literally yawned.
The people who have to spend the money to make this content have to be sure that the general public is willing to pay for it. As far as I can tell most people are very content with 1080P upscaled to 4K. Mind you I would love 8K but I was in the HT business and I learned to listen to the customers. A few will pay anything for the best but their numbers are not nearly enough to justify production companies, broadcasters and providers to make the jump to 4K right now in any great numbers much less a jump to 8K.
BTW I was lucky enough last year to watch a small part of a TV series being filmed in 1080P and I asked one of the camera men how much does that Sony Camera cost and he said about $60,000 US for the camera alone!!
He then said and oh yeah we use about 20 of these to shoot the series at the various locations. I don't even want to guess at what the 4K version of that Camera cost. That is just one of the smaller expenses these companies would have to endure.
