While I agree in principle, there is the problem, that you need to find a new good device before you can retire your old one.

The N900 is my phone for 7 years now and I would have loved to replace it with something more modern for at least half of that time.
But I just couldn't find an alternative. Android, Apple and MS are out of the question, because I don't trust them. Besides, even if I trusted them, there were few devices that I actually liked from a HW POV.

Although I still use my N900 it's always been some love-hate thing, mainly because I'm frustrated with the limitations that are a consequence of Maemo's proprietary core. The N900 has tought me not to settle with something that is "semi open" again.
This is why I didn't get a Jolla and it's also why I hope the Librem 5 will become true, even at the cost of a hardware keyboard, which I would not even have considered two years ago. I guess I'm just growing desperate.