The problem may just be that the business model that works on Apple's app store - direct sales - doesn't work as well on Android.

David Edery: "Triple Town did 67% of its iOS revenue on GooglePlay. Confirms what I'd heard: f2p games are probably the way to go on Android."[1]

Chris Pruett: "@djedery Indeed, Wind-up Knight is more profitable on Android than iOS."[2]

[1] https://twitter.com/#!/djedery/status/185800787581091841

[2] https://twitter.com/#!/c_pruett/status/185802890688991232