I think they mean the software support lifecycle from the time of release, not how long the physical hardware lasts.
I also have relatively positive experiences with Chromebooks but also you can buy a Dell Latitude used on ebay and get the same experience. My $200 shop laptop from 2015 (Latitude 7450) which I only stuck an SSD into is going strong despite being kicked, stepped on, dropped, having oil and acetone spilled on it, melted a bit, and subject to other such garage abuse. (Though it is on its 3rd $15 keyboard)