Enjoyed skimming through all 14 pages of the discussion.
Everyone's reasons for changing or not changing their devices are different. But I think the most important two reasons are budget and lack of necessity
I don't think anyone has mentioned this yet, but there are some people who haven't even updated their system in years. It's really common now to see people who use for example OS X Mojave or Catalina, or older, even though their devices are capable of being updated to newer version.
Coming back closer to the topic - I believe we now live in those times, when technology development has dramatically slowed down and that is why many people can't even feel necessity of an upgrade.
My example. I still use two Macs: iMac 2017 running Ventura 13.6.1. I use it primarily for really heavy tasks - a lot of open pages in Safari and Chrome, tens of photos in Photoshop and a project in Figma. It still works just fine and I can't feel that I need to upgrade
MacBook Pro 13 2015 with macOS Mojave. I use it mainly for light tasks like working with documents, MS Teams, Zoom etc., but it's still capable of doing some work in Photoshop without any big problems. I also use it when I travel somewhere and need a portable computer. Do I really need to get a replacement? Definitely not