You can't say consumers use iPad3 and Nexus7 for e-reading, no backlit screen is suitable for e-reading, regardless of pixel density.
The new Kindle E Ink e-readers hopefully use the plastics based flexible and unbreakable E Ink screen, if they do, the new Kindle can be ultra thin, ultra light and basically unbreakable, that would be awesome.
But just as the new Epson or others new higher pixel density controllers for E Ink, the flexible E Ink requires significant mass production to be mass produced. That kind of is logic, so it's to be seen how soon there can be some significant large mass production done on those fronts.
Signage is a gigantic trillion-dollar market, with hundreds of millions of advertising billboards and posters worldwide, I don't see why it should be a problem for E Ink to try to deliver solutions for that market. Doesn't it sound awesome that advertising billboards can potentially just use color E Ink in the future? Also, what's wrong with supermarkets using E Ink for centrally and instantly being able to manage pricing of everything on the store shelves.
I also really like E Ink's suggestion to use the back sides of smartphones as an E Ink screen to display data and use the back sides of smartphones for much more comfortable and much lower power consumption for reading any text.
So really, there is only a few brands like Amazon that have the power to get the component makers to launch the mass manufacturing of new generations of screen technologies, but who knows, it might still be too early for flexible plastics based E Ink to really be mass produced at the quantities that Amazon requires, so perhaps Amazon has to stay on Pearl E Ink still for now, perhaps with a new thinner Neonode IR touch implementation for the touch kind.