> Apple had a good run, I've genuinely enjoyed using their platforms daily, but I'm afraid they're dropping the ball now.
I haven't owned a (personal) Mac since High Sierra. The UI had been going downhill since Yosemite in my opinion, but gradually; it took a nosedive with Big Sur (I think that's the one that introduced all the SwiftUI apps?) to the point that I realized I probably wouldn't own another Mac until they figured out that a Mac is a computer, not an iPad. Looks like they still haven't yet.
That being said, I believe that 10.5-10.9 is probably somewhere close to what peak computing looks like. It's not perfect but it makes sense to some degree. I had no problem teaching people of any technological skill level how to use Snow Leopard or Lion; and not just getting by, properly becoming competent computer users. On the other hand, I've been watching my parents (both of whom have been using computers since the late 70s) slowly lose the ability to "understand" both modern macOS and iOS, and are more and more frequently struggling to find old and new features and functionality (like being able to see all of their emails on their phone).
It's disappointing really. For a while I couldn't stand using Windows and regular Linux desktop distros were too fiddly to be useful, and Mac really was the best option for "I just want to do X" with the least friction. Nowadays, Windows sucks for a whole host of reasons, and the Linux desktop is more usable but still Linux, and apparently Mac has decided to shoot itself in the head. If my grandmother asked me what computer to replace her Mac Mini with if it died right now, I really don't think I'd have an answer.