Profits and usage are different categories. Apple might be taking more money home, but that's not what is being discussed. The points being made were about having control and influence over the ecosystem.
Our team has become more and more focused on supporting two platforms with our App Development effort, Apple and Samsung. 75% of our users have an iPhone 5S or newer. The remaining 25% is a mix of Android, other iOS devices and older iPhones. Of the Android users, 80% are using some Samsung device.
Because iOS users are a significant source of potential profit.
Apple doesn't need to maximize usage in order to control the ecosystem - they just need to maximize profit potential.