1) Has anyone actually articulated *WHY* they would want to run Android on the Pi? That would be about the same as running Android on a desktop PC - which I see no point in. Anyway, Android's mostly for things like dating apps and Candy Crush and such things. Not really things that make sense other than on a phone.
2) The point of the Pi is to be a standalone environment. From early on, the guiding principle was that it should be something that a kid can own (outright) and be able to mess up if/when he pleases. These are conditions not true of the family desktop PC. So, having to have a desktop PC as part of the mix (in order to develop for Android) defeats the concept.