NeXT was great and Mac OS X was also nice and had a lovely indie and boutique app ecosystem during the mid-to-late 2000s. Sadly, iOS stole the focus. However, the OP argues Linux usability is bad, which I think is an outdated POV. It really depends on your setup and usecases. For many development usecases, Linux is superior to macOS.
I run NixOS on a plain X11 environment with a browser, an editor and a terminal. It's really boring. For my favorite development stacks, everything works. Flakes make workflow easy to reproduce, and it's also easy to make dramatic setup changes at OS level thanks to declarativeness and immutability.
If you're interacting with other humans, or with the consumer internet, you'll run into thousands of situations where my default setup (macOS, Chrome) "just works," and your setup will require some extra effort.
You may be smart enough to figure it out, but most people (even many smart tech people) get tired of these constant battles.
Here's an example from earlier this evening: I was buying a plane ticket from Japan Air Lines. Chrome automagically translates their website from Japanese to English. Other browsers, e.g. Firefox, and even Safari, do not - I checked. Is there a workaround or a fix? I'm sure you could find one, given time and effort. But who wants to constantly deal with these hassles?
Another very common example is communication apps. Or any time you're exchanging data in some proprietary format. Would it be great if no one used proprietary formats? Yes! Is that the world we live in? No. Can I force the rest of the world to adopt open standards, by refusing to communicate with them? No.
The world has moved on from desktop environments to multi-device integration like Watch, Phone, AirTags, Speakers, TV and in that way Linux usability is certainly worse than MacOS.
Oh sort of. That is for sure a thing, but not THE thing.
I would argue people are being tugged in that direction more than it being simply better.
You can bet when people start to get to work building things --all sorts of things, not just software, they find out pretty quickly just how important a simple desktop running on a general purpose computer really is!
I run NixOS on a plain X11 environment with a browser, an editor and a terminal. It's really boring. For my favorite development stacks, everything works. Flakes make workflow easy to reproduce, and it's also easy to make dramatic setup changes at OS level thanks to declarativeness and immutability.