Look but don't touch

Google has been tightening its grip on Android:

While Android is open, it's more of a "look but don't touch" kind of open. You're allowed to contribute to Android and allowed to use it for little hobbies, but in nearly every area, the deck is stacked against anyone trying to use Android without Google's blessing. The second you try to take Android and do something that Google doesn't approve of, it will bring the world crashing down upon you.