> What's the reason for the upgrade? Camera?

I’m convinced that the camera quality degrades as the phone gets older/more used. What convinced me was my mom receiving a brand new 6S replacement from Apple and seeing the major camera improvement even though her broken 6S was in mint condition.

Can anyone provide some insight to this? It took years of speculation for us to learn our slower OS/battery concerns were real. I’m wondering if this is next.