I like that my Flip 4 can be tiny and then be large depending on the use case. But I don't see upgrades as important anymore. One time, circa 2009 and such an upgrade meant immense improvement, more features, better UI with each software update, but that hasn't been the case since 2015. Today, it's more cameras, a larger and more unwieldy device, and nothing to differentiate one brand from another. Software is pretty flat and stagnant as well. It's just not as important to upgrade anymore.
I bought my Flip 4 hoping I'd have it for life. It's the only 'unique' model left after carriers killed my Thunderbolt, and I spent a ton to get the highest storage, 5G, and memory capacity (RAM). I spent hours configuring the UI to at least resemble my Thunderbolt (quite convincingly). I don't really see any need to change unless a more unique model comes out, and the only other reason is if they ever do to 5G what they did to 3G, but I probably have 20 years to find out if that happens, and hopefully by then smartphones won't be a thing anymore. Or I won't need one period. I am trying to future-proof myself. So far my Flip 4 has detoxed me, I don't spend nearly as much time on it, so it's become a glorified Moto RAZR and exists just to call, text and be an MP3 player.
Maybe I'm just old but I tend to keep things until they break irreparably. I would have gladly stuck with my HTC if carriers didn't unethically force me to upgrade against my will. It would have been nice if ONE carrier made up their own mind and kept 3G going, instead of being a sheep and copying everyone else. Replacing a perfectly good working device with another that's maybe only slightly better is wasteful to the planet, encourages e-waste, upgrade culture, and disposability. I will never understand why people buy replacements for things that still work. But here I am still using CRT TVs, Windows Vista/7, and 8-tracks.