Why not take it to the extreme end of the argument. Why not go back a Core 2 iMac - you can code, read docs, analyse data etc. on those machines right? Install Linux and you even have modern software. It's slow but you're only human 🙂Why? Human brains aren't going to be faster in 2035, so why would you need an "M8 processor" for things like word processing, reading pdfs, reading webpages. Things like AI are computationally heavy but they'll probably run in the cloud as they do now.
Are you saying that you complete your work 2.5-3X faster? Benchmarks do not translate to faster humans.
As I said earlier the invention of GPU-accelerated tasks, and SSD, revolutionised the desktop. Beyond that, it very much depends what kind of work you do. But I would be willing to bet most people are not even close to hitting the limits of Coffee Lake.
Coffee Lake machines are noticeably slower and add friction to everything you do. You don't have to be pegging the CPU to benefit from the performance and quality-of-life difference.
I had a Coffee Lake Refresh 16" MacBook Pro, every single interaction with the machine was slow and cumbersome compared to the M1 machines that replaced it. Electron apps ran like crap, video calls would bog the whole machine down, background tasks like indexing would sap performance, even just web browsing was enough to get the fans spinning. I had to carefully manage my multi-tasking load to prevent the machine from slowing down and heating up 😅
I could swap out my M3 Pro for a Coffee Lake and do all the same things, but it'd add friction at every click and keystroke. I would definitely be less productive and the problems would only worsen over time 😬
Choosing a much older, slower machine with far fewer years of usable life left for a brighter screen is not something I would recommend, but you seem happy so more power to you 👍