Who knows... Android is basically Linux, and is supposed to be fun... Then again, it's locked up, so you have to root the phone to do anything remotely interesting. Which in some cases, like, for example, Wildfire S is not even possible without extra hardware.
Then the platform is quite limited, low power, small displays, A6, A7 revisions of CPUs. There are few apps that sell well, I guess, and if you can come up with a revolutionary idea, then you might earn something.
But you really have to think of something cool, because all you do, is mostly small apps, so no-one will want to spend 50$+ on them.
Then there is all that "malware market" stuff. You either use Google app market, or you're stuck with weirdo markets you cannot trust. Most software houses don't provide APKs directly.
And the whole platform is a privacy nightmare...
I have an Android, and from one point of view, I'm interested in programming something for it, but from another, it's really limited, and I have no idea if there is even a way to get money out of products you develop.
Then again, I'm not a teen that only plays with his phone, so I treat it as an emergency internet source and a phone. I guess teens might use all those fancy apps, but then again, it's a market segment with limited funds to spend on software.
Hard to say...
Metro will be available in next Windows phone if I'm not mistaken, but so far, Windows phone seems like a total disaster from what I heard. And Android is also taking over iPhone from where I see.