I'm still not sure why.
The section doesn't really answer the actual question. It's cheaper, good enough, replacement parts are cheap, and I understand that argument; I myself use alternatively some kind of very old Thinkpad (that I don't remember the specs of), a 2011 Macbook Air, or a recent Macbook M1 and for what I do with them (little more than running Firefox and ssh) the only difference that matters in practice is their screens.
But replacing a Macbook M1 with a Thinkpad only makes sense if the Thinkpad is better in some aspects, not if it's just good enough. Otherwise you would just keep your somewhat better laptop and replace it later if you ever have to, right?
I like Macbook hardware, but I left because MacOS is only getting worse. It's not hard to sympathize with others who feel the same. Nevermind the downward spiral of design trends and wasted screen space, Apple has made no efforts to improve MacOS as a compatible dev platform. UNIX certification means very little when the most popular open source software is broken out-of-box on your OS, and your hardware vendor actively avoids implementing open APIs like Vulkan. There's no point for me to buy a laptop that Apple owns.
For many people, it's less about the hardware and more about telling Apple to fuck off. I'm among the latter, getting kicked off MacOS when Apple made the overnight decision to depreciate 32-bit software. Onwards to greener pastures, I suppose.