Well, Amazon bought out Audible and has now come out with Kindle Unlimited. The monthly subscription fee is cheaper for the Kindle Unlimited but those don't go on an iPod. A Kindle doesn't hold its charge as long as an iPod and is larger. So is Amazon trying to get everybody to do everything on the smart phones?
Did Amazon buy Audible to choke it off? I don't see why it couldn't have done that without buying Audible.
This isn't a case where they seem to have merged their libraries.