I can't go into a Starbucks, Panera Bread or a Barnes & Noble without seeing at least a couple. Just because you don't use yours doesn't mean that other folks don't find usefulness in the form factor. The market has matured, Apple is not refreshing the line as often as the early years and people are not replacing them. I still have my Apple Air and it works great!! I use mine all the time, whether it's reading an e-book, casually browsing the net or some late night viewing before I sleep.
Phones are fine when you're on the go but even at 5.2 to 5.5" I'm not doing anything serious on the phone.
If Apple ever develops a version of Logic for the iPad Pro I may say goodbye to my laptop and desktop machines all together.