They are. I suspect most e-paper goes into much smaller displays.
But it is getting there, perhaps more so than people realise. There are also working colour e-paper displays now, although it's usually black and white plus one or two other colours rather than *full* colour.
Three colours:
https://www.youtube.com/watch?v=8A5w0z3vVRQ
Seven colours:
https://www.youtube.com/watch?v=0JAB45vpQlk
So right now, you can either have colour, or speed, but not both.
Biting the hand that feeds IT
