Apps are what separate a dumbphone from a smartphone. And app developers that make paid for apps are going to develop for the platform with the biggest installed base, it's that simple. iOS 7 runs on all iPhones from iPhone 4 onwards. The iPhone 4 came out at the same time as the Samsung Galaxy S (not S3 or S4, the S!). Is anyone still using a Galaxy S? No way. So despite much higher current sales of Android phones, a good chunk of them are replacing old Android phone that stopped getting OS updates years ago. That's not expanding the installed base.
On the Windows Phone front, the platform had a reboot with WP8 less than 2 years ago. How many people are still using WP7.x devices? Not many. So again, a lot of WP8 devices are replacing WP7 devices and not expanding the installed base. WP has the double whammy of low sales and high replacement rate.
And everyone wonders why iOS gets apps first!
On the Windows Phone front, the platform had a reboot with WP8 less than 2 years ago. How many people are still using WP7.x devices? Not many. So again, a lot of WP8 devices are replacing WP7 devices and not expanding the installed base. WP has the double whammy of low sales and high replacement rate.
And everyone wonders why iOS gets apps first!
