I don't see many scenarios where someone could practically use a 55" in a desktop environment though. You'd have be sat 2-3m away at least, which in most typical arrangements won't be possible. I have 32" at present, and could certainly go to 43", although I may have to wall mount to push it that extra 10cm back that I think would be required. Any bigger and you're getting too far beyond the FOV of the human eye which means you're eyes and head will be moving all over the place.
I'm not sure I see a market for monitors much bigger than 43"... and even that size is going to be a niche. Heck, we've seen precious few 32" 4K monitors in recent years, with the focus being more on 27" 4K/1440p, so I don't know we'll be getting a 49" traditional 16:9 anytime soon... previous few people would be able to utilise that size outside of a lounge, hence why the 65" BFGD exists (again niche though). With TV's on the horizon with HDMI 2.1, A-Sync and 120Hz displays though, you could probably find something here if you wanted to go that big.
The
Samsung CRG9 49" Super Ultrawide is intriguing, if only because it's such a crazy thing to look at, and definitely has some WOW factor.
As for 8K, give it a decade at the rate monitor tech develops!