Yeah, people forget how buggy macOS has been. Both Snow Leopard and Mountain Lion were public admissions that they needed to focus on quality. They haven’t had a proper one of those in a while.
That said, I can’t remember a time when bugs have been as long-standing as they are now. SMB file shares have been completely broken for nearly 3 years now (the solution is to buy the program AutoMounter), and USB-C docks have been broken since day 1 and still are on Big Sur.
I use a usb-c dock with some version of OS X on my work laptop and it totally works 28/30 days. The other two days I usually notice it’s not working when the CPU throttles because the battery is now at 4% and is “not charging” (I still haven’t figured out the difference between the “charging” and “plugged in but not charging” icons.)
Personally I think that the quality started increasing between the first few releases (i.e. tiger better than panther, or at least definitely better than jaguar), but it then started decreasing at some point. I would not be able to say which release was at the "peak".
Indeed, MacOS 9 was buggy as hell and worse than Windows 98 in terms of stability. OS X apparently fixed some of that for a couple of years, so it looks like Apple is now reverting to its old ways.
It definitely is. I just got a new 16" MacBook Pro and have had several ridiculous bugs. I frequently have to delete the keyboard layout preferences file in order to set it to ISO.
The most annoying one is that the whole thing crashes if you unplug it from a dock while it is asleep. You can get around it by setting it to never sleep while plugged in, but guess what? That setting magically resets itself if it crashes.
