Pixel 8 to have seven years of Android updates
I feel like the elephant in the room is that there's no phone battery that's going to stay useful in anywhere close to that time frame, and replacing phone batteries is usually a losing proposition.  I've tried, several times.  Fake, low-quality batteries are rampant (usually degrading within weeks), and genuine ones are prohibitively expensive -- usually a significant fraction of the cost of a new phone.