I will give you a hint: developers for Microsoft and Google are the same. Why is Android more successful?
Hint: Android (Samsung) innovates for us: multi window, IR remote, Miracast etc etc
Without Samsung there is no 80% market share, but hardly 40% and independent developers aren't reason we buy Samsung phones
Stats are obvious = pure Android is just a base = does not matter on the market
If everything depended on developers there is no logic for the Samsung's (Android) success.
Samsung was successful even without a bunch of developers a few years ago, it's simply not true, proved.
Success of any ecosystem depends mostly on the owner of the ecosystem or if the ecosystem is opened depends also on luck if there is a powerful developer. Android was lucky = Samsung was found, brought features, brought marketing = wins for Android = developers are not so important as you think, Samsung has proved that.