It's a soft force, you become dependent on iCloud, universal copy and paste, shared calendars with F&F and many other proprietary features which discourage you from leaving.
I've been using my Android phone for nearly 2 years, it has all the same features as my iPhone, but if I switched to it exclusively, I would make my life worse and no longer be able to share photos with the family or know what events they have planned.
It is designed that way. in the same way I used to give free server monitoring to my hosting customers or your ISP gives you a free email address.