e-Ink feels like a prototype we're putting up with because it has some intrinsic conceptual advantages, but it never feels like it's fully there yet. It's probably the most utilized such technology I can think of (though perhaps I've just gotten more used to other tech's flaws). I'm happy we're willing to do that, really, but e-Ink is unsatisfying and needs to be better.
Unfortunately the latter are arguably more widely applicable, and vivid color displays are reallly easy to sell to consumers, while the charms of something like eink are more subtle up front (even if very apparent in the long term). Eink-type displays, that emphasize long-period eye comfort and texture over vivacity and color, are probably a smaller niche.
Niches don't really get the money... and subtlety doesn't sell.
Oh well.
There are also (at least around here) vast quantities of poster-sized dynamic advertising displays in pedestrian walking areas that are used "statically" (only update maybe ever minute or so). Right now they use giant lcd monitors for this (hung on the wall like a poster), but they've got to be sucking up a lot of power...
Eink with improved contrast and color support would be very useful...
http://en.wikipedia.org/wiki/Flip-disc_display
The magic of e-ink is in making the pixels small enough to provide a useable resolution on small screens.
One of the earliest applications of eink (before eink "paper" was a thing) was actually in advertising signs with huge feature sizes (10s of cm), so big pixels are not something new to eink.
I saw a video a few years ago, where someone had bypassed all that, and was running an eink display at video frame rates. It seemed to work fine.
[...google search...] Ah, here's the video: https://www.youtube.com/watch?v=24srQXX81Oc
There are other similar videos, by other companies, too.
So for a device where more power consumption is acceptable (compared to a power-sipping e-reader), fast-update eink displays may well be possible, and even practical... but it's not so clear anybody is putting much investment in such a thing...
And the reason it isn't here is not technical problems -- it is because some shaved chimpanzee of an MBA thought high quality E-readers without colour (or a battery good "just" for a few days) was too small a market?!
I have vertigo.
(The reader MaysonL mentions doesn't seem to be on sale yet? I don't see review from 2014, at least?)