This interesting article on how to read Kindle books on non-Amazon devices almost inadvertently highlights a key problem with investing heavily in Amazon content.
Doing so places you in a walled garden you can only "escape" from (and take your content with you) if you're willing to break the law and illegally bypass the digital rights management on your Kindle ebooks.
That’s quite a wakeup call when you’ve invested hundreds, if not thousands, of dollars in Amazon digital content.
Not only does this illustrate one of the many reasons DRM is bad, it also shows yet another example of how Amazon is not the "reader's friend". By utilizing a proprietary format unlike any other in the industry, Kindle users are finding out that they can legally read their ebooks anywhere they want…as long as it's on an Amazon device or through the Kindle app.
E-Ink device users? With a few exceptions, you’re just out of luck. Unless you buy a Kindle, of course.