Marco has implied that he makes a "six figure income" from it (on the Planet Money podcast) but has never given more details than that that I'm aware of.
My reading of a lot of the commercial Android developer pieces is not that it's impossible to make money on Android, just that where you have limited resources it tends to be the case that they can more profitably be utilised on iOS work. The issue for someone like Marco where it's just him is is less can you make money in Android (with or without ads, that's kind of secondary), more is working on an Android version going to bring him more money than putting that same effort into keeping Instapaper close to the top of the iOS pile.
Obviously if you're a company with several programmers and you're happy with that model then so long as the cost of building an Android version is less than money it brings in, it makes sense because you can just bring in someone else to do it without detracting from your other work. If you're a one man band (or similarly small outfit) with no interest in taking on and managing more people it might not.
Essentially he was talking about what an iOS developer "might" earn. If memory serves he pitched that the equivalent of a six figure salary was possible / reasonable if you were successful and I think agreed that that was the sort of thing he was getting.
Obviously that puts it at between $100,000 and $999,999 a year, so fairly wide error bars on that.
My reading of a lot of the commercial Android developer pieces is not that it's impossible to make money on Android, just that where you have limited resources it tends to be the case that they can more profitably be utilised on iOS work. The issue for someone like Marco where it's just him is is less can you make money in Android (with or without ads, that's kind of secondary), more is working on an Android version going to bring him more money than putting that same effort into keeping Instapaper close to the top of the iOS pile.
Obviously if you're a company with several programmers and you're happy with that model then so long as the cost of building an Android version is less than money it brings in, it makes sense because you can just bring in someone else to do it without detracting from your other work. If you're a one man band (or similarly small outfit) with no interest in taking on and managing more people it might not.