Nobody saw it happening when London overtook Rome many years ago as the biggest city in tbe world.
And nobody is seeing now that Android is slowly overtaking ios as the superior platform.
Like a lot of Apple diehards in this thread alone, Apple is taking for granted what people want in an ios device in 2017 and taking for granted the offerings of Android relative to ios.
Sales may be going well for Apple at the moment but if Apple keeps up the incremental change appraoch, they will start losing ground. Every year Android becomes more and more refined. The days of poking stick at Android for being a disjointed, laggy and malware prone software are long gone. People who still assert that today are stuck in 2012. Things change, except Apple's philosophy of increnental change. London overtook Rome and Android is catching up to ios.
Incremental change won't get you more market share, but continued refined improvement and added features which add to the user experience will.
I give it 10 years before Apple loses its crown as the smartphone king. Look at what happened to Nokia. Things change.
This is based largely on what happens with these bendable screens both Apple and Samsung are working on. How each approach it will go a long way to deciding who is the biggest seller in a decade's time. Knowing Apple, it will build a fold out screen device to simply mimmick an ipad-like screen. Think Plus model which really didn't offer anything to take advantage of the extra real estate other than offer extra real estate. And knowing Samsung, it will do a lot more than that, it will be Note 8ish-like where the wow factors will be through the roof.
Apple, you've been warned, change your approach or be the next Nokia within 10 years time.