They'll be issues of high end smartphones in 2/3 years, too.
I agree with OP on this. Updates (of any kind) on smartphones are toxic as fuck.
Honestly, 3 years is more than enough to upgrade again...
This is not a console, it's a device we use every single day of our lives for many hours while at that. If it's ok to update to mid gen consoles after 3 years, and then to another gen 3 years later, on a device for solely entertainment purposes, I don't see why updating phones every 3 years would be a problem. Most people use phones to work/research/watch movies/videos/play games and so on...
I think it's unfair to ask for something we use to that extent to last 5 years or more.
Personally, I update every single year and it's the best possible scenario for me: I sell my current phone for a good price, pay a small price to update (usually $100~$150) and I always have my phones under warranty for that reason on top of that.
If I waited 5 years to update, my current phone would worth almost nothing, so I'd have to pay $800 (or even more) from scratch or so. That's more than the symbolic price I pay to update every year. Not worth it.
Bet with Teeqoz for 2 weeks of avatar and sig control that Super Mario Odyssey would ship more than 7m on its first 2 months. The game shipped 9.07m, so I won