I don't think 8K holds a lot of appeal right now.
8K is a lot of resolution for even a 30" monitor. The mainstream segment is going to want a monitor that sits on a regular desk; not everyone has computers connected to TVs, or large monitors mounted on walls.
I think you'll agree that the general physical size of a monitor has increased. Old monitors were good enough as 15" when they were CRT or old TFT. Then I first came across a 18.5" monitor in 2008, and now, in 2015, I got a monitor that was 22". I'm saying all this because I'm a mainstream customer and mainstream is what drives business. And I don't envision the size of a mainstream monitor becoming too big - an average user will want a monitor that he can easily look at from say 2 feet away and can read all text shown comfortably.
8K monitors may come, but they could take a long time: graphics cards of today aren't really capable of driving 4K displays; 4K 60FPS is hard to hit at good graphics settings on current games on any single GPU.