The killer application for these e-ink dispalys is calendar/todo list display. I'd love to have my org-mode agenda and todo-list/notes on such a low-powered, low-refresh-rate e-ink screen.

I know this question has been probably been asked many times, but I'll ask again: why are these devices not mass-produced in great numbers? Clearly there is great market demand for it, so then why would the market supply not respond to this demand? Is it because the technology has some oddities that manifest in tricky manufacturing processes? Or is it some patent encumbrance issue?