In the iOS vs Android case, iOS does in fact typically bring at least 50% more profit to developers, often far more.
iOS sure brings some value to the table. How much actually ? who knows...
For comparison Youtube is also a platform regularily criticized by its participating creators, but you're not seeing high profile lawsuits or the EU slapping them fines at every turn.
What you’ve said doesn’t change this at all.
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.
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.