Well I struggle with the processing demands of individual frame 36MP images, let alone a 24 or 60 fps stream of them.
I have a 4K TV (55") but apart from the smoothness of the fonts in the text that is added to the footage, I can't really tell the difference between HD (nationally broadcast, netflix or blu-ray) and 4K footage (from Netflix) from a normal viewing distance where I would watch this size of a TV. Furthermore I am not in the slightest bothered by SD material on DVD compared to broadcast FullHD; if the content is good, either works fine for me (even excellently). For nature shows such as those made by BBC, FullHD is advantageous, as well as for some sports where there are many players visible at the same time, but for movies, I'm fine with DVD quality. I just don't see a purpose in going from FullHD to 4K or beyond even if the material was available to me. It's a different situation with photographs which can be printed large and viewed and studied for a long time, and let the details "sink in"; when watching films, I'm interested in the plot mainly, and wouldn't pay much attention to how much detail there is since the images are changing.
I can see the idea of using a 4K or higher TV set for slide-showing photographs though I prefer the permance of prints. Even for stills I find 24MP or 36MP adequate for any need I might have, and mostly shoot 20MP nowadays. 12MP was a little too little though. I think adding pixels is largely just a waste of storage space, computing power and thus also electrical power and natural resources. The internet is already consuming a large chunk of our energy and increasing the amount of data would necessarily entail increased need for the production of electricity that might exceed all other uses (and thus result in increased pollution and global warming).
