There's not a single feature added to phones during that time worth replacing working device for average user.
Also not being stuck on an ancient version of Android - though I don't know what the custom ROM community for that phone is like, perhaps some soul is still porting newer versions to it.
https://redmine.replicant.us/projects/replicant/wiki/GalaxyS...
which seems to be outdated by about 5 years now
https://redmine.replicant.us/projects/replicant/wiki/DeviceS...
i admire how long devices could be used, if they just were to receive security updates...
If hardware manufacturers published a list of their own patches to the source tree (rather than the typical "single commit/zip file of the entire linux kernel") then it would make community maintenance of old devices much easier.