I assume it's only a matter of time until the texture (or appearance of texture) of the screen can be changed from super-cinema HD to easy to read in direct light paper-like something - assuming there's a market for it. Younger generations have a very different relationship with tech.
You can't change the laws of physics.
Not to get pedantic, but I'm going to anyway.
LCD/LED (phone/tv/computer screen) works like a slide projector. There's an extremely bright light, and you hold a semi-transparent image in front of it. The bits the light shines through are the bits you see.
E-Ink works by 'surfacing' microscopic black/grey particles in a white/pale grey medium. The only thing you can see is the bit light bounces OFF of - mostly the page, rather than the writing. In effect, there's almost no difference between this tech and spraying or fusing black dots onto a sheet of paper - aka printing.
That's why I will only read books using E-ink, as it's equivalent to reading a printed page. I find it soothing, especially as I do most of my reading in bed before I go to sleep.
Now, people who consume all their media on their phones probably don't care if they also read books on them. It's unlikely they're going to carry around a kindle AND a large phone, that's for sure. I would guess that people reading books on phones outnumber those reading them on dedicated e-ink devices by a factor of 100,000 to 1, to be honest, given the number of phones out there.
I'm just pointing out that you can't display a book on a phone the same way you can on a kindle, and if you're trying to convert a 'paper only' reader then possibly the worst thing you can do is show them a book on a bright, glaring phone screen, rather than a page on an e-ink device.