None of this account for differences in purchasing power and phone price.
If you have an $150 Android device, I would of course expect you to spend way less on software than somebody with a $1500 iPhone.
I’m not saying ‘develop for Android only’ but if your business relies on one ecosystem only, you’re at a higher risk and you’re leaving money on the table.
Well, that’s common law for you.
Most of the world has continental law where most of these things would be written in a law somewhere and unenforceable through TOS as those provisions would be deemed in conflict with the law and therefore void.