Depends on the game/monetization method. I'm fairly confident (without having any data/just guessing) that Pokemon Go generated more money on Android than iOS

Depends on the game/monetization method. I'm fairly confident (without having any data/just guessing) that Pokemon Go generated more money on Android than iOS because there's more devices and I don't think iOS users are that more likely to ingame buy for this particular game. Also if you use a free+add based model I'd once again say Android would do well. For a one time buy game that's relatively expensive like MarioRun I agree with your statement though. And I'm sure the exclusive partnership with Apple has other benefits, being announced at the KeyNote is great free marketing for example.