Many wouldn't. On the other hand, we see lots of people here who only change their phones when they are forced to, so increased longevity would clearly be a good thing for them as well as for the environment and reducing the waste of finite resources. And once the hardware longevity is improved the next thing that may force you to change is that apps won't run (because the OS is too old) or you feel insecure because you've not had a security update for years. So improved software support addresses those things.
And phones are mature products. To be honest there is little materially that has changed between my 2013 HTC One and my current Galaxy s21. The camera is better (HTC messed-up the m7 design, and the camera sensors got damaged by heat), though far short of a real camera, the phone is larger (a negative), and it has 5G (though where I live hasn't), but it doesn't do anything fundamental that the 10 year old phone doesn't. So in some senses a lot can change over 8 years, but in reality it's all incremental now and there's no sign of that changing (bar foldables, but they are still expensive and fragile, and for me don't yet address any need). So honestly if they would make it a more sensible size, and if I didn't already have a phone that is less that 2 years old (and hence a bad thing environmentally for me to replace it) I would be happy to give them a shot.