I've felt the same way. I went from crappy low-end Android devices when I had no money in school to a Nexus 4 and I haven't seen reason to upgrade since. The only reasons I've done so have been because I cracked a screen and because I wanted to hand down a device to someone else. Been sitting on my OnePlus One for a few years - looking at the market now and not seeing any reason to upgrade still.

Worse, I get worried about some newer devices which may make me less free - the Pixel has a very locked down boot process and the Magisk developer has been struggling to support it. I currently use Android Pay on my rooted device and I'm definitely not willing to pay to lose that freedom.