I can’t think of anyone who upgrades their phone other than normal hardware reasons, i.e.; cracked screens, decreased battery performance, etc.
Perhaps your peer group has a higher level of vanity around their phones than normal.
Can you provide a specific of someone you know upgrading their phone because their neighbor did so?
People who complain about others upgrading their phones are actually half a version of keeping up with the joneses.
Spending mental cycles on the possessions of others is the first criteria towards keeping up with the joneses, the second half is the purchase to keep up.