DRM from a technological perspective is broken, simply because it uses encryption in a wrong way ... the user being both the party that receives the message and the third-party from which the message is protected. This means the decryption key is easily obtained by inspecting the device's memory or hardware or by listening to packets sent over the network. This is why to date there is no DRM scheme that wasn't broken somehow, as the technology is fundamentally flawed from a technical perspective.
For Kindle, here's a collection of 4,687 mostly pirated books in Mobi format that you can copy straight to your device: http://thepiratebay.se/torrent/6748422/Kindle_Library___%284... ... do you really need more proof than this?
Because really, if DRM doesn't protect against piracy, and it doesn't, then what's its purpose, other than lock-in of legitimate customers?
And I've worked for BigCo, I know how they think. Lock-in is not something that just happens. Lock-in is a planned process.
To give technology partners something (broken) to sell to publishers so they'll agree, in exchange, to publish their catalogue in a digital format. It's like giving someone a (broken) gun so they'll agree to let you go on a date with their daughter. You know it's broken, and they might even know it's broken--but it's the act of doing a "good-faith effort" to protect the publisher's content that matters, not the consequence of whether it gets cracked or not.
The purpose of DRM is to get you, the legitimate user, to pay multiple times to use the same content. They want you to pay once to read the book in your kitchen and another time to read the same book in your bedroom and another time if you want to let your wife read it too. By definition, you've already paid once so you're an excellent candidate to get more money out of.
The purpose of DRM is to make it hard for you to use multiple devices, hard for you to use different platforms, and so on. So that you'll pay again. These aren't flaws. They're design goals.