Going beyond 4K makes sense ... if you sit at a distance from the screen about the screen height or less, so less than half the screen diagonal. I suppose people could do that even with moderate size screens, like viewing a 30" diagonal screen from 15" away, or 40" from 20" away, but I really do expect it to happen with any home screen size, even in the long-term.
Assuming you didn't miss any "no"s in the above passage, I disagree. It is very
hard to setup a living room to allow for 100" plus screens in homes or apartments. You need proper viewing distance, for the screen to be close to the floor, and clearance in front of the screen.
It's no problem for those of us who can dedicate a room for a home theater, or are such movie buffs that they put cinema before feng shui, and
can afford such a setup, but for the 99% it's not an option; especially with 4k which asks them to drop a few thousand euros to replace their 1080p TV they just bought a few years ago.
Caveats: the upcoming generation watching movies on their laptops might change things as they are comfortable sticking their noses to a big screen, as would heads-up-displays, direct drawing to the eyes with a laser, or contact lenses with screens on them (all of these are at least on proof-of-concept stage, no scifi).