There are probably some reasons that, combined together, will cause slow demise of e-book readers. Some of them are listed in the article, like the declining number of people who actually read books, or little real innovation in the world of e-readers. I may add a couple of my own observations, which made me give my Kindle to my son and switch to a tablet instead.
- Being locked to one ecosystem. As much as I like Kindle, I occasionaly read books that are unavailable in its format (like older books that have been scanned and are available on Google books). The same goes for many non-English books. To read these I need a tablet which is not tied to just one e-book ecosystem.
- I read many academic books. While Kindle is OK for fiction, it is less then ideal for textbooks, academic books and generally non-fiction (because of complex formatting, tables, illustrations, footnotes etc.)
- To make notes I can easily attach a (bluetooth) keyboard to my tablet. This is impossible to do with a Kindle. Also, there is no note-taking app on Kindle, like Evernote or OneNote and the note-taking functionality of Kindle itself is too limited for my needs.
- Too few ebooks formatted for Kindle use real pages. This makes quoting them very awkward. Conversely, most books available through Google Books have real page numbers.
- PDF support on e-readers is erratic. Some readers will display some PDFs, but they can't be relied upon.
- I seriously considered buying the new Oasis, mainly because of its being waterproof. But the price is so steep for what it can do that I stayed with my tablet, buying a cheap waterproof case (or rather sleeve).
That said, I hate Google Books being tied to the ADE system, which on the whole is much more restrictive than the Amazon's one, so whenever there's a choice, I still buy books from Amazon.