I'm sure a large percent of the PC users are content also. It's not like iOS is some magic piece of software. I've been using it since iPhone 1, and it has really regressed a lot since iOS 6. My parents have trouble doing a lot of things that should be and used to be easy. I have trouble too from time to time.
As for me, I am still using a 6.5 year old, 11 inch MacBook Air. I have wanted to upgrade for a year or two now but Apple has yet to give me a compelling reason to do so.
It is unbelievable that they have not been able to produce an air with a Retina display in that time. The 12 inch MacBook is the closest they have come, but that has its own shortcomings that have kept me away (no MagSafe, single USB port, keys that barely move when you type on them). The MacBook pros are nice but even the smallest, thinnest one still weighs more than my old air.
If Apple had made an 11 inch air exactly the same body as the one I bought over six years ago and added a Retina display I would have bought it immediately.
I think if Apple expects people to upgrade every couple years then they should give people more compelling reasons to.
Marketing of old was "I am a PC" which always left me feeling like the PC guy, not the wise ass Mac guy. Apple has always had this snottiness about PCs, which probably appeals to the hard core Mac audience but is mostly impenetrable to the "I am a PC" guy because he is going to look at the iPad Pro, see it has no keyboard and no mouse and costs however many hundreds, and he's not even going to think of buying it despite whatver snottiness Apple rains out.
They quoted such a high price for repairs that I was able to purchase a Chromebook with 4GB of RAM and an Intel NUC with 16GB of RAM for the same amount. Both are running Linux, and I'm very happy.