As an Apple shareholder, your article doesn't fill me with optimism. iOS phones are now nearing, or already in, the single digits in market share with Android crowding a 90% market share for Q2 in 2016.
The ability of Apple to survive as essentially a one-trick pony depends on having a fantastic trick, with no other ponies doing equally fantastic tricks. Let's face it, mobile phones are a commodity: they make telephone calls (more or less), take point-and-click pictures, provide Web access, and run small computer programs. Short of exploding batteries, screens that are designed to break with minimal force, and the user-relative desire for pocket-size vs. portable TV-size, they're all pretty much the same. Most of the world don't even have smartphones and the likelihood that they can afford to upgrade in the near future is pretty small. In wealthy economies that can afford smartphones, there is a little room, but not a lot as a fraction of market share. Apple's probability of capturing the remaining 1/3 of Americans who don't own a smartphone is, well, in the single digits.