It's not always about being uncool. Sometimes it's about your current device getting slow enough to be annoying, so you want to replace to avoid paying the daily mental tax, "death through thousand papercuts", coming from the single piece of electronics you use most of, day in, day out. And that is caused mostly by software bloat - as mentioned elsewhere in the thread, between OS updates and app updates, a year is about how long a flagship phone has before it starts to become annoying to use. And then it only gets worse.
Somewhere along the way, you pass a threshold where it's uncool to have a certain version of phone and judging from what you hear about the waste problem with phones, it's above the reasonable moment to get rid of it because it's broken or not usable.
I mean, sure it's a nice lie you can tell to yourself, but in the end, it's not good.