What with news breaking today that Amazon had released a new Kindle Paperwhite, I thought you might be interested in seeing how much Amazon's ebook reader had changed since the first model launched nearly 7 years ago.
The gadget comparison sitehas put together an animated gif that morphs the first Kindle into the second, etc, finally ending with the Kindle Paperwhite. The gif leaves out the KDX, and it also skips the Kindle Touch (not a bog deal, IMO), but it does give us an idea about just how much Amazon's design philosophy has changed over the years.
As you can see, the first 4 generations of the Kindle kept certain constants: page turn buttons, a d-pad (or its equivalent) and several bask buttons (home, menu, etc). There is also a clear trend from the second model onward that shows Amazon choosing to shed buttons, first thinning out the keyboard, then dropping it entirely, and then removing all of the buttons.
As someone who still fondly remembers how cool the keyboard was on the original Kindle, I think they went to far. But judging by the lack of griping about the Kindle Keyboard going out of stock, I could be the only one who feels that way.