macOS as Unix is not dead – the compatibility with developer and unix infrastructure it has is an important reason why the company I work for uses MacBooks (at least I believe so).
We've found it to be a much worse experience than windows for dev stuff. It's a different OS and architecture to the target env (Linux). Aligning with that makes life considerably easier.
The relevance of Open Group and the UNIX brand has been a walking corpse for decades.