There's little doubt Amazon have changed the world; their are the canonical Internet retailer, as envisioned by Jeff Bezos twenty years ago, and have become "The Everything Store". But the thing they've really done is eliminate books. Well maybe not eliminate them entirely, but largely. How long has it been since you bought ... an actual book? Unless it has beautiful color illustrations or is really old and/or hard to find, there's no practical reason not to buy the Kindle version, right? You pay less for it, it will last forever, it takes no storage space, and you can read it anywhere, easily, on your Kindle, or your iPad, or even on your phone...
I prefer reading on my Kindle during the day, especially outside, and on my iPad at night (my Kindle isn't backlit), but I'm amazed at how often I end up reading on my iPhone. Standing in line at the store? Waiting for someone? Eating alone? I whip out my iPhone and poof! I'm reading. Maybe it's not the perfect experience, but it's quite good enough, and certainly beats the alternative; who carries a book with them everywhere, in case you have a few minutes to fill?
When the Apple iTunes App Store first opened for business*, there was soon a funny little saying: "there's an App for that". Which became somewhat jokingly, "your product, there's an App for that", as camera and GPS sales plummeted. Which became somewhat less jokingly, "your company, there's an App for that". Now we can say, "your industry, there's an App for that"; as physical books go the way of records and CDs and videos and DVDs and all other media content.
I'm eagerly anticipating becoming a Glasshole (getting a Google Glass :), and wondering what reading on a Glass will be like?
* Hard to remember now, but the original iPhones didn't have third-party Apps; it wasn't until Apple enabled this capability that smartphones truly took over the world.