Don't, they'll just shred it. Sell it on Ebay and let it be harvested for spare parts.

Even if they reused the parts, the less wasteful phone is the one you already have.

I am not trying to be overly moralistic though .. just trying to understand if there is any value people see in getting a new phone each year outside of social/new and shiny.

It made a lot of sense 8 or 10 years ago where each year there was a big leap. But nowadays, even for e.g. camera, the improvements are very incremental at best (when they are not mostly algorithmic so backportable) .