Well, thank goodness it's not here, sounds like the sort of person who would argue for no valid reason. Which I've just had enough of. If you look closely at the work of that sort of person...which I deliberately avoid getting into here because it's off subject, they can't even accept what's on subject, and they have better knowledge of those things.
I can see what he means, that you can't see 12k pixels/or monitors. But, the little field of view we use is below 8k, but a full field of view would be three times across, so it would be below 24k, but that's basically a vr display. I was in communication years back, with a company with 16k vr displays, doing a 32k design. The 12k is still 3x acceptable 4k screens. I don't like the uneven division into 8k, but at 4k it's even.
There are higher resolutions than 720p. But they can publish stills, and cut out a 720p subframe and display that in video to show image quality, and people can stand 9 times back if they wish, to make it similar size to a real life display. Pixel peeping is really great though, blow up to see if it is cleaner and nicer than the competition, becomes more obvious. Then view full screen, and see if it looks nice anyway.