Even assuming that a nice backlit AMOLED is preferable to ink on paper in good light (which I'm not sure is true), physical books have pages that are easily turned, quick random access to different parts of book, and lots of subtle cues to reader about current location, etc. This is an advantage over ebooks.
Ebooks can be digitally searched, which of course is an advantage for them. But it's hardly clear that any electronic reading experience is hands down superior to physical book in all situations. And if one were it would not likely be an ebook in a 5" form factor, that's too small. 5" is good for portability, but for sitting down in a chair at home for a 1 hour session, I can't imagine anyone preferring a 5" smartphone to a larger tablet. (I say all of this as someone who probably reads 40% on 4.5" smartphone, 30% on 13" laptop, 20% on 8" tablet, and 10% physical books.)