I'm not sure where you're taking your figure of twice as much, but I assume it's the AppStore vs Google Play break down ?
That number is the total revenue for the whole store (there's a lot to say about it, since Google is also not the only Store for android, in particular in China and Korea), and it matters very few for any individual developper.
It's not because the total amount of in-App purchase for all games is twice as much on iOS that my new ssh shell app will make twice as much on iOS than on another Store, for instance.
Most US developers are not producing versions for Chinese app stores. That’s a red herring.
Of course individual products have their own idiosyncrasies, but is it in fact the case that on average, an app on iOS will make more than the same app on Android.
That number is the total revenue for the whole store (there's a lot to say about it, since Google is also not the only Store for android, in particular in China and Korea), and it matters very few for any individual developper.
It's not because the total amount of in-App purchase for all games is twice as much on iOS that my new ssh shell app will make twice as much on iOS than on another Store, for instance.