EVery time someone changes their smartphone they are tosing several hundred Euro worth of camera gear into the bin.
Not really. It's a multi-purpose device. That your house has a refrigerator in it does not make your house a refrigerator. That your car has a radio in it does not make your car a radio.
And the actual camera unit on the back of your average phone costs about $25 to replace (part - not labour).
You can still use the camera functionality of a phone that is no longer being used for anything else. If you throw it in the garbage, that's your choice.
But would you throw a Sony a6000 in the garbage if you bought one of those new Sigma BF cameras? Would you throw away a Nikon F2 if you got a Nikon f3?