And while you can still find an traditional unix(tm) box here and there in the dusty forgotten corners of enterprise serverooms(i am personally responsible for maintaining a few hpux boxen), unix(tm) certification haven't really mattered since Linux became serious business which happened around the same time OSX was launched.
What used to matter was that you could run the same CLI tooling in an macos desktop as on an Linux server but i don't think this is an use case apple see's as particularly important for the future success of Apple.