Solarpunk

Well, long before that the device would stop working. More important would be improved repairability. My current phone is in year 4 and the hardware is starting to die. But I can't replace the battery or other parts that start breaking. 20 year software support means nothing without that hardware lasting that long.

In that regard I think 7 years is already plenty. If they pair that with easy to replace batteries and screens that would go a long way.