The problem with the Monument Valley numbers is that they expected a hit game on iOS would magically translate in to a hit game on Android and that's really not the case.
The two stores are completely separate, your popularity on either will not help you on the latter unless you're bringing a big marketing budget with you or have something truly unique and viral.
There are plenty of popular Android games that have virtually no player base on iOS.
The two stores are completely separate, your popularity on either will not help you on the latter unless you're bringing a big marketing budget with you or have something truly unique and viral.
There are plenty of popular Android games that have virtually no player base on iOS.