macOS is more than shiny traffic lights buttons on your windows, global menus, and dock.
It's also a clipboard that works everywhere and not like "oh you cannot do this because X11 this or wayland that", it's also human interface guidelines (the old ones, the new ones are unparseable shit) that make bloody sure that the OK/Cancel buttons appear where you expect them to appear.
It's also some bloody keyboard shortcuts that work everywhere the same and not every bloody app bringing in their own and their own little ways to configure them or none at all. Yeah chrome, I'm looking at you.
It's also that the most used system stuff can be configured pointy-clicky and that stuff that the system can figure out on its own is what it bloody figures out on its own, without me having to drop down to command line (although it is an avenue too, and command line and GUI must be in sync).
It's also that it's accessible out of the box. Try blindfolding yourself, inserting your installer usb stick, and installing your thing and using it successfully. Come on. OS X could do it since Leopard, I think, which was in... 2007?
In other words, macOS could abandon their Aqua looks and go for industrial NeXTStep looks, and still be ahead of almost everything else in terms of consistency, accessibility, and general lack of fuckness.