My understanding from every report I have ever read is that there just isn't a lot of money in Android apps. Not a lot of developers share, but those who do tend to report underwhelming results compared to what I see from iOS shops (and those who develop for both platforms have said exactly that in no uncertain terms). For example, Kreci posts his profits every month, and the monthly average is something like $1300 from 10 apps, several of which are pretty popular. All the news stories I see about the Android Market seem to agree with this. If you have better information, I would honestly be fascinated to hear.
(I don't mean to impugn Kreci's success. He's well within the range he wants to be in for where he lives and I'm nothing but happy for him — but for where I live, that's rent on a cheap apartment.)