I think the answer is simply that Ubuntu has become good enough. The whole point of running MacOS was to get POSIX compliance with a polished GUI. No Windows,

I think the answer is simply that Ubuntu has become good enough. The whole point of running MacOS was to get POSIX compliance with a polished GUI. No Windows, pretty terminals smooth fonts good UX. Now MacOS has no edge over Ubuntu in any sense. Ubuntu runs Docker natively and Cuda. It has an insanely user friendly installer, it runs on a wide range of hardware with no issues and its default GUI is great.