Weirdly all my android phones are still working. I upgrade on average every 2 to 3 years, current phone bought a flagship 3 years ago and other than battery deg

Weirdly all my android phones are still working. I upgrade on average every 2 to 3 years, current phone bought a flagship 3 years ago and other than battery degradation it's performing as it was when I first purchased it. I am actually using my older models for various automation tasks and one as a webcam for video calls from desktop. Maybe the problem is when buying cheaper models?