@Seed,
Personal understanding is that Android was a civilian system, multi-user, low cost, the developer more than the threshold is low, the user can choose according to their preferences, or think you want a large number of software.
Apple user’s three hobbies: photo, game, blog.
Android three hobbies: reflash firmware, restart, replace the battery.
Symbian (Nokia System) three Hobbies: throw phone, wrestling phone, drop phone.