It sounds like this is in need of a decent upgrade system, where one can easily access upgrades of different kind and also deal with the disposal/recycling of the outdated parts (no gain from the recyclability if the parts end up in the landfill). With that said, the same system may also offer different kind of phones (if one f.ex. realize after a few months touchscreen ain’t as convenient as a qwerty, one can get another phone) so I imagine a monthly fee for a phone that is always up to date, but not to have the same phone (or plastic shell, or any one part of the phone) – a transition from a product to a product service system.