That's amazing, I wasn't aware 8k has been around for so long. I assume footage was upscaled since I can't imagine many productions using 8K cameras (if available) back then. I'm unsure if you can even get many decent titles in 8k now!
I know of a few tech youtubers recording and uploading in 8k, soon going into 12k (but YT doesn't support beyond 8K yet).
Resolutions beyond “Full HD” have been around over 20 years albeit in low volume theatrical applications , big big expense
The nyquist theorem works for video as well as audio.
A 4K TV only resolves 2K to your eye.
We've been making 8K in japan work by using 4x4K signals for the last 8 years or so.
Is 8K enough? That all depends on the size of the screen and your distance from it and what you are trying to present - if you want a razor sharp screen in vegas thats hundreds of feet tall - no.
For your living room I suspect we'll be top at 8K a while until entire walls are actually screens in the home.
My guess given all the extremely strangely shaped sets in large sizes used as display walls and promotional boards I almost bet we will end up in a strange place with “docked content” screens going to the home as a niche.
We already have an “iPhone proportioned” aspect ratio set that can be rotated vertically to better view cell content on a wall in the niche.
Give it a few years and a cockpit view in the high end might become a thing where multiple viewports can be setup displaying different content with auto sense and zoom/distort on by default, 4:3 sets may even make a comeback to better utilize floor space. We already have a translucent screen, have it lit and alterable between opaque and clear and that might be an office thing for show.
Given that 16:9 TVs are fully commoditized I will guess there is a fire under tv makers rear to find a new thing to justify, 4K and 8k didn’t move the kneedle much and super wide is too low of volume for profit even at the astronomical prices.
Ah well see what the future holds, 3D failed, 4K became a commodity in a few years, see what else hits the wall