Apple will continue to sell it because profit margins. The entry level 16GB option sells the best and will continue to be well into 2020. There's no escape. If less people opted for it and instead purchased the next in line 64GB version then Apple may reconsider.
I will be buying a new phone in the next week or so because I'm switching carriers and can either take a $500 subsidy or leave it if I keep my old phone.
I have a galaxy S4 (when I upgraded from the iPhone 4S, my only important feature was the larger screen). My wife currently has an iPhone 6S+.
I admit I absolutely hate Android (or is it Samsung's Touchwiz crap). But I hate Apple's outdated hardware and software. I'm trying to decide between an S7 edge 32 gig or an iPhone 6S+ 64 gig. The android is $70 cheaper from my carrier, but the price difference is a minor issue. It feels like there are only bad choices on the apple and android side.
The screen on the android is absolutely stunning, graphics are just beautiful and when I put it next to the iPhone 6S+, the iPhone looks like last decade's refuse. Looking at the OSes side by side, android looks sleek, smooth, and modern with it's widgets, slide out panels, etc. And the lack of a hardware back button on the iphone feels like a missing appendage at this point. Split screen multitasking works amazingly well on the S7 as well. iPhone has fallen so far behind in hardware quality and basic functionality I feel bad for Apple.
But the android is so full of bloat, a lot of the controls actually feel clunky and convoluted, and so much basic stuff is hidden in non-obvious ways that I think the iPhone is much easier to use. I also am a big fan of the sort of security Apple has on their iPhones. I don't even really install Apps on android anymore because I hate the messages like "this App will download your address book to the software publisher, take it or leave it." I know Apple isn't perfect, but I do have confidence they screen out a lot of the apps that try to do that on their phones.