Apple's AppStore sells 90% more than Google's.
People who buy Androids are mostly the people who just want to have a touch smartphone "like the other people", and keep themselves to the preinstalled apps, or pirating games off google.
What about people who want expandable storage via SD cards?
What about those who want water resistance?
What about those who want an OMLED display?
What about those who want a higher resolution display?
What about those who want better battery life?
What about those who want more RAM?
What about those who want more for there money?
Galaxy S7 offers all the above with 32GB storage (again expandable via the SD card slot), 4GB ram (double!), for cheaper than the entry level 16GB iPhone 6S, and that's one of the most expensive Android phones you can buy. CPU, cameras and build quality are on a comparable level. HTC 10 and LG G5 are other respectable flagship choices that offer similar specs/performance/quality. The only thing Apple has that Android doesn't is force touch.
You can also get a decent mid-range phone like the Moto G4, and although it may be missing touch-ID and have slower CPU and a poorer camera, it's only $200, less than the third of the price of an iPhone 6S!
Personally I think Apple is nuts thinking they can get away with selling so little at flagship prices. One at a time people get fed up, try Android, find out it's actually pretty darn good and stick with it.