Also, pixels densities don't scale linearly. Having a 200 DPI desktop screen isn't equivalent to a 200 DPI laptop screen, else phones would still be at 480 x 270 or whatever.
Also, pixels densities don't scale linearly. Having a 200 DPI desktop screen isn't equivalent to a 200 DPI laptop screen, else phones would still be at 480 x 270 or whatever.
It's like how people will buy an 18MP camera with worse optics instead of a great 12MP camera because it has a bigger number. And god forbid they ever need to make a 20x30 print, you wouldn't want to see any pixels in that.
To take the opposite extreme of your 480 x 270 cell phone example: You can get an Xperia Z5 with a 5.5" 4K screen, but that doesn't mean it makes any sense.
Your comparison with phones would be more convincing if they ever really took off, but as far as I'm aware it never happened.
Typed on a Razer 13" with QHD display that I'm still constantly messing with (FC25 Cinnamon).
The "visual threshold" doesn't mean "you will not see anything smaller than this so it cannot physically matter". You can still see a hairline even if it's less than 1/300 inch wide.