It might be just me - but my phone battery degrades so significantly after 3 years that the phone isn't worth using anymore, so I'm not that bothered about not receiving updates past that window.
My 5 year old phone is still at 84% battery capacity. I set a charge limit to 80% unless I'm planning to be away from a charger for some time and set it to go to low battery mode at 40%, which discourages me from draining it too low. I wasn't even this careful for the first couple of years that I owned it, and I use the fast charge mode.
You can change the battery in most phones (there are plenty instructions on youtube how to open the case or do it with some service center), that's much cheaper than buying new phone.
On chinese marketplaces there are batteries for almost any phone, might be in your local marketplaces as well, depending on location.
This is a very solvable problem, at least for me. I only charge when I'm running low on battery and my phone tells me to and I never interrupt the charge cycle once it is plugged in.
I've been running a Galaxy S7 since 2016 like that and only now do the first battery issues slowly start to appear.
