[Ajedi32]

Interesting question.

My understanding is that modern printers actually mix those four different inks together on the page to achieve a wide range of colors. That isn't possible with a display where colors have to remain within their own separate (sub)pixels and can't actually mix together.

With a high enough resolution that might not matter, as your eyes would be unable to discern individual subpixels, but this display is only 600×448, and that's with only one subpixel per pixel. (A CMYK display would need 4; maybe slightly less depending on subpixel layout.)

Furthermore, modern sRGB displays can output 255 different brightness values for each subpixel. This display can only output 7 values for each pixel. That further reduces the number of possible colors which would be possible in a CMYK subpixel-based display.

Provided all those issues could be solved though; maybe it would work? There could be other considerations I'm missing. (E.g. Can subtractive color mixing even work with subpixels in the first place?)