Other than your carrier give it for free or cheap, I don’t really see the reason why should you buy new phone. I’ve been using Redmi Note 9 for past 3 years and recently got my had on Poco F5. I don’t see the point of my ‘upgrade’. I sold it and come back to my Note 9. Gaming? Most of them are p2w or microtransaction garbage or just gimped version of its PC/Console counterpart. I mean, $400 still get you PS4, TV and Switch if you don’t mind buying used. At least here where I live. Storage? Dude, newer phone wont even let you have SD Card. Features? Well, all I see is newer phones take more features than it adds. Headphone jack, more ads, and repairability are to name a few. Battery? Just replace them. However, my Note 9 still get through day with one 80% charge in the dawn. Which takes 1 hour.
I am genuinely curious why newer phone always selling like hot cakes. Since there’s virtually no difference between 4gb of RAM and 12gb of RAM, or 12mp camera and 100mp camera on phone.
Performance gains for certain software or games. Especially if you are into emulation then the higher power of newer flagships or better cooling design, mean that you can run more recent games on your phone. Same thing goes with camera lenses, better camera means you can get better shots so if you are into photography it makes sense to upgrade.
Thrift wise, there is never really a reason to upgrade as long as it still texts and makes calls but the non-phone features are why you would upgrade early.
Or getting a non-phone for your usecase.
That’s always an option and often cheaper. But people would rather use the device they always carry on them rather than having to carry a laptop, emulation handheld, or DSLR camera with them all the time. People are willing to pay premium for the convenience.