It's funny how people like to brag about their display size...and yet it's never enough.
Well, there is the car / penis theorem about an inversely proportional correlation in size, it might be the same here.
OT - For PC screens there is no difference for the average person (which actually manages better than 20/20 on visual acuity) beyond around 186 DPI.
Which in turn, is roughly the DPI of a 24 inches 4K screen. For 5K, the minimum size baloons to around 32 inches. For 8K, that would be around 48 inches.
So, I doubt there will ever be the need for more than 5K on PC screens - not accounting here for wider displays, which would skew the "5" on 5K towards a higher horizontal resolution.
There won't even be a use for TV screens since at around 4K the maximum distance to notice the resoltion is around or below the diagonal size of the screen, so even if TV screens increase significantly in size, it's very likely viewing distance will proportionaly increase, unless you want a strained neck from looking above or missing detail below your line of sight, depeding how low or high the middle of the screen is positioned.
Not to mention processors are going to run out of litho shrinks and the exponential improvements that came with them, so for gaming and virtual reality, you would possibly be sacrificing some measure of photorealism for imperceptible resolution, since the most powerful consumer GPUs ever conceived will run out of juice before doing both.