You’re absolutely right that I don’t know a ton about Android, but I DO know that Android’s fragmentation problem is very real regardless of whether it’s the fault of carriers, phone makers, or whatever, and it seems to be getting worse http://www.businessinsider.com/android-fragmentation-is-worsening-2017-11. iOS developers focus on the newest OS because the vast majority of iPhone users are on the newest OS, which lets developers and users benefit from and take advantage of the latest technology. With over 50% of Android users on versions that are over 2 years old, Android developers are stuck building their apps for inherently inferior (and less secure) OSes if they want to reach the biggest market. That’s a concession and a handicap, not a feature, as well as a big reason why iOS has the best apps (or at least gets them first).