20/20 vision means you can separate two lines 1 arcminute apart, which means 0.5 arcminutes per pixel, or 0.25 arcminutes assuming vision twice better than normal, which some people have.
So, since 180*60/0.25 = 43200, the optimal theoretical non-uniform planar screen is a 43200x43200 screen, where the peripheral pixels are enlarged to support almost 180 degree FOV (excluding the last pixel that would require an infinite screen).
If one wants uniform pixel size and limited FOV, display size needs to multiplied by (2 * tan_deg (fov_degrees/2))/pi
For example, 120x120 degree FOV gives 47634x47634 size (would be rounded up to 48000x48000), while FPS standard 90x60 degree FOV gives 27502x15879 (would be rounded up to 28800x16200).
Thus, at 12 inch = 1 foot distance, 120x120 FOV with 40/20 vision requires approx. a square 60" 48000x48000 800 dpi screen, while 90x60 FOV requires approx. a 16:9 40" 28800x16200 800 dpi screen.
Now on a phone it's hard to focus on the screen when holding it close enough to the eyes to obtain desktop-like FOV values, so maybe one could get by with less, but still those resolutions would eventually be required to support desktop-sized video files without loss.
We have a long way to go, we are not even close to optimal screens.