My hypothesis is today's "modern" OS user interfaces are objectively worse from a usability perspective, obfuscating key functionality behind layers of confusing menus.
It reminds me of these "OS popularity since the 70s" time lapse views:
https://youtube.com/watch?v=cTKhqtll5cQ
The dominance of Windows is crazy, even today, Mac desktops and laptops are comparatively niche
But for whom and to do what? People around me, like my wife and mother in law, are happy with an Android phone. If they use a computer, the only thing they need is a browser.
I wouldn't be surprised if 90%+ of all Windows users would use Windows for one thing: click on a browser icon.
That's why after one malware too many I confiscated my mother-in-law's Windows laptop and got her a Chromebook.
I'd say that's why the shit UI/UX doesn't even matter anymore for most users: the only use a browser anyway.