The amount of people without a "Microsoft/Apple/Google smartphone" (ie. not running iOS, Android, or Windows Phone [sic]) is very low in absolute and relative n

The amount of people without a "Microsoft/Apple/Google smartphone" (ie. not running iOS, Android, or Windows Phone [sic]) is very low in absolute and relative numbers. You might run say Sailfish OS, they have an Android emulator. Backwards compatibility is extremely important in the software ecosystem.