Because it's still a great time as app developer.
The picture above (via @waxpancake) speaks two things at least. First, Apple must be selling tons of iPads. Second, iOS users are active and proud of using Apple device. As an iOS developer, these two things are good news.
And this report from CNNMoney is not a good sign for Microsoft and Sony. People don't wait for Santa to come at their homes anymore. They just go to Apple Store apparently.