Apple is one of the companies that can really get away with an en-masse OS transition simply because they are basically guaranteed to get 80% on board in less t

Apple is one of the companies that can really get away with an en-masse OS transition simply because they are basically guaranteed to get 80% on board in less than 6 months simply because they control the distribution mechanism and the device hardware itself. They can plan for these transitions. Google and to a lesser extent Microsoft screwed up and are struggling to be able to keep their users on the latest and greatest. This is such a huge advantage for Apple that it can't be overstated. On Android at least 36% of devices are still running Gingerbread (which is 2.5 years old). Android 4.x is finally up over 50% after being out for just over a year and a half. So, whenever Google gets around to Android 5.0, it will probably be a whole year later (or more) before that is the mainstream targetable version of Android. As a developer, you could argue this gives you more time to get around to building against the new api's, but at the same time that's remarkably slow user uptake compared to iOS.