I'd counter that by pointing out that my phone is the single most-used piece of technology. Setting aside its communication functions the sheer number of devices it has replaced makes it a with: camera, videocamera, PDA, iPod, alarm clock, car GPS. It's also my notebook, address book, and calendar. It controls my lighting and my TV. It tracks the quality of my sleep and replaces the white noise generator that I used to use to get there. It's the hub where that sleep data goes, along with the data from my scale, blood-pressure cuff, and watch (heartbeat, exercise) go, along with the calories and nutrient data from my food tracking app. I have a widget in my car's OBD2 port that logs my performance and trip data to the phone; and I get automatic reminders to move my car before the meter runs out or the space becomes a street cleaning zone. And when I'm taking MUNI or BART, the 3rd-party apps are more accurate wrt/ arrival times than the transit agencies' own displays. It replaces the Nintendo DS and Kindle I used to use to keep occupied when riding transit or airlines. I can also use it, and the watch, to pay my bill at many stores and restaurants. And none of these even touch upon its usefulness for work. I could knock out another whole paragraph for that.
Given the amount of utility I get out out of it, if there's any piece of technology which really does justify having the top of the line, the iPhone really is the one. That said, I do stick to the the 2-year cadence and get the s-models. Though if the 5s hadn't been able to store credit cards for use with the watch, I'd have early-upgraded to the 6 to get ApplePay. Happily, the 5s plus watch did that job, so I'm still on the s cadence.