> Android has shipped a lot of handsets, but the users don't seem to like to pay for apps.

This may be true, but then look at the profitability of some free apps paid for by advertising: http://www.droidgamers.com/index.php/game-news/android-game-...

Given that this is recurring revenue and not dependent upon new sales (though, yes, dependent on new content packs), I'd say it's pretty well done. With the caveat that Angry Birds is the outlier, not the norm.