Why do you find "all of them" answer to be unsatisfactory? Development of same or similar technologies by entities other than E-ink is possible only under one condition: those entities are safe from patent infringement lawsuit. With only a few specific patents expire/get knocked down somehow it would still be impossible to find investors bold enough.
> Yes. But how is that related to what I asked about? ... Because expensive based on what calculation?
You've made an analogy with Windows and I've offered an explanation of why OEM licence of Windows preinstalled on a notebook isn't seen as expensive, unlike e-ink screen of a €900 picture frame.
> It has nothing to do with patents.
Well, you might be right. Maybe it's impossible to manufacture e-paper screens at a significantly lower price point. Maybe it's inherent to this specific technology and no amount of competition and investment will be able to fix it. But we will not know it for sure any time soon. Because of patents.
