They should be consistent, discoverable, and customizable.
I give macOS full marks for consistency, and a passing grade for customizable, but it's hardly discoverable! I read these kinds of HN posts because of all the little tips and tricks I find.
Operating systems used to come with a thick manual, and you could buy an even thicker "missing manual" book at the local bookstore. macOS could use one of those.
I think that's what 'intuitive' means, practically, in this context.
Of course, physical things are losing buttons. I guess kids will refer to things as 'tap the tappy spot' or some such.
But then there are core features like "a file icon on a document window can be dragged exactly like a file icon in the finder" that you can use macOS for years and never find. That's before they started hiding the file icons in Big Sur!
macOS is packed with little things like that.
I think it's fine that they hid it, since even before, the things you can do with it (dragging, cmd/ctrl-clicking) were already hidden.
The only old functionality that is lost with Big Sur is that you could glance at the icon to see if there are unsaved changes (if so, the icon would be dimmed). But you can still tell by looking for the dot in the red close button.
One thing that's killer for me in MacOS vs Windows, regarding consistency, is text fields. They always behave the same (except, of course, for weird apps, say ms office). CMD+Backspace will delete a whole word even in password fields or system settings, etc. This is always hit or miss in Windows. I know it doesn't work for passwords. In Windows explorer it works... sometimes. It works in the address bar, but not in the preferences or when renaming a file.
why ?
I find the "app-less desktop" of Windows and all the Linux DE's I've tried (i.e. the big ones) far more weird and infuriating. It's easy to lose context of what app is focused, since a slight dimming of buttons isn't quite as obvious as I'd like. Reading the word of the app in the menu bar, even if it's just through my peripheral vision, makes the focus behavior far more obvious.
And an "app-less desktop" more or less necessitates that you now dedicate an entire meta/super/Windows/whatever key to the window manager, which is just such a waste of keyboard real estate, as well as a driver for key command inconsistency. In macOS, Cmd+N will (nearly) always make a new window for the app that you're in; Cmd+W will close it; Cmd+Q will quit it. In Windows, Cmd+N works for everything, but to make my first file explorer window, I have to hit Windows+E. And to quit an app, it's...Alt+F4, for some reason?
The trickle-down effects of this design are endless -- I've just laid out the basics of the basics here.
I find OSX to be generally pretty logical and easy to understand, but certainly no more _intuitive_ than something like Windows. Another way of saying this: if I took someone who didn't know how to use a desktop OS, I wouldn't be any more confident sitting them down in front of a Mac.