also camera just not being satisfying enough anymore is a big deal

sure on highest end phones you have very good cameras since a long time by now, but even there they find improvements here and there (e.g. zoom, low light pictures, even better image stabilization)

but middle to lower end phones are still have major improvements in every generation of a certain brand/line/price category. And you might be satisfied with a "acceptable" quality camera, until everyone around you has way nicer photos, or you now have a reason to make photes you didn't had in the past, or you get older and your hands a bit unsteady etc.