To put things in perspective for you, App Store has been giving me daily less than 10% of the total mobile downloads, and around 15% of the mobile sales. Now with the decrease on Android downloads, it becomes more relevant but still not comparable to Android. In my case discoverability on iOS is nonexistant, you're found only if someone looks for you or you get lucky with the "similar" games. Or, as I believe is often my case, because an iOS user sees your game on someone's Android and then looks it up. But who knows, that's just my case, very likely I got algorithm-lucky on Play Store somewhere in 2016 but it could have happened on App Store, or on neither.