Not every film has to be made with the latest technology. Sticking with analog or black-and-white or 24fps is a perfectly valid artistic choice. But it's an artistic choice made by the film creator, not some advantage to the older stuff. Cinemas should be using the most accurate reproduction they can. Filmmakers can then dial it back in the actual film if they think that's better.
The comment I was replying to wasn't saying 8k might produce worse results sometimes, it was arguing that 8k and higher fps would just be worse, period.
Then, let's look at the reproduction part only.
Technically, it might work. More choice in reproduction. But maybe in the real world, movie theaters (and certainly in the television world!) would crank up the brightness and edge sharpening and frame interpolation to make the director's artistic material look totally horrible.
If you think about the whole life cycle of any kind of art delivered to some audience, it's lined with these huge pitfalls at every point.
Maybe I'm obsessive compulsive about it.
Likely a lot would depend on good defaults and good training. If you were as skeptical about people and organizations as I am, you would assume it could on average worsen many movies. The original Murphy's Law and all that. :)
Say, your cousin has been cooking as a hobby for a while. They move to a bigger house with a new kitchen and can finally get a big spice rack and a deep frying machine. They proceed to deep fry everything and put all possible spices on it. It tastes bad and monotonic.
Your friend plays in a band. They've been gigging a while and got new PA equipment that they say sounds less muddy than their old cheap crap. You go to a concert. The treble is so harsh you can't stand it and have to leave.
Some examples where some new tool is, in theory, better. But it turns out a worse end result because lack of skill in using it.
I find many technically oriented people don't understand this. They point out to some number saying "well this makes it absolutely better". Sure, numbers might be easy to measure. But it's the end result that's important to most people.