> Studies show that someone with 20/20 vision (or 6/6 in Europe) can distinguish something 1/60 of a degree apart. This means 60 pixels per degree [...]
NOOOOO!
"Resolution" is defined as the closest distance two dots can be while still appearing as two distinct dots. If you have two dots shown on adjacent pixels then you just see one big dot. You need the two dots separated by a pixel in order to see that there are two dots, so the resolution is half the pixel pitch. Worse yet, the two dots might be diagonal, so you need an extra factor of sqrt(2) in your resolution calculations. This means that the pixel pitch of a TV screen is 2 * 1.41 ~= 3 times its resolution. You need 180 pixels per degree if you have 20/20 vision, not 60.
And it gets worse. Everyone knows that 20/20 vision is "normal". Well, not quite. 20/20 vision is the average without correction. Once you include glasses, 75% of people can actually see better than that, and some quite a lot better. So to be safe lets bump the pixel density up by another third, to 240 pixels per degree. That gives 7,200 pixels on a 30 degree screen.