I'm skeptical of this. People buy new phones because they are faster, or because they did update and the new version of the OS is very slow on old hardware. People buy new hardware because they want new hardware.
Most non-tech people I know actively avoid updating their phones because it's annoying. They will ignore the notifications and choose older software over the inconvenience of updating and rebooting their phone.
Avoiding updates and ignoring notifications could stem from a different reasons. People may not want to take the time and maintain their phones. I consider myself a techy person, but I also put off updating my phone, taking good care of it, upgrading it. I also dread tidying up my room, getting a hair cut, shopping for clothes, eating healthy, sleeping well etc. It could be a personality trait.
Avoidance conserves energy :)
I think the mounting cost of e-waste is a far bigger deal. Think of the unimaginable amount of carbon impact from the millions of trashed Android phones out there. Do we really want to continue down this path, until there's billions of obsolete machines sitting in landfills (there probably already is)? Updatability can save devices for much longer, and now people are upgrading less often, there's a huge opportunity for impact there.
Disclosure: I work for Google, but not on the Android OS or Fuchsia.