That the purpose of it is to advertise economic resources is not true. My wife has an iPhone because it's the most competent tool she can use to get the job done. Having used several Android phones prior to this, I don't blame her. Relatively speaking there are fewer security issues, compatibility quirks, and reliability issues with iPhones which makes them worth the price to her.
After the 2 year mark our Android phones are literally in the junk drawer, and her iPhone 6s is still functioning as fast as the day it was purchased.
It always amazes me how difficult the android experience can be. I have always had Nexus devices and the "pure" google android is pretty easy and clean. My parents hand me their verizon phones and I wonder where the features and simplicity went. I'm amazed they tolerate the clutter and crap on their phones. Android can be nice and it can be crap.
As for a 2 year shelf life - I'm still on a 2013 Nexus 5. It runs smooth and runs everything I need. Isn't a 6s only 2 years old?
I'm still rocking an iPhone 5. I use it mainly for browsing, news apps and spotify. It has the latest OS, all new apps are usable (except games of course).
Recently the battery got swollen, I took it to an apple shop and got a replacement (a refurbished iPhone 5) for 100 dollars.
I've tried android twice and both times were bad experiences but from recommended phones from people. My first iphone experience was bad (iPhone4) but I picked up again from 6s plus and never looked back.