Pour one out for BeOS. Unix-based, lightning-fast GUI, process isolation, and no user isolation on a single-user machine. They got quite a few things right 20 years ago.
It had Bash and partial POSIX compatibility, but you're right -- it wasn't Unix.
BeOS was awesome as an OS built ground-up for affordable GUI-capable personal computers. It was incredibly responsive and capable at a time when the PC alternatives were Mac OS (crashy), Windows 95 (lots of legacy baggage), and X11R5 on Linux (a clone of a knockoff of a mainframe OS).
IIRC the PARC systems cost $20k or more in today's dollars, and were strongly tied to a single programming language. (I've read about them, but haven't used one.)
Presuming everything else went the same way elsewhere in the ecosystem, Unix greybeards might have become very excited about Android or ChromeOS and the "developer hype" might have pushed Google into making one or the other a workstation OS.
(Or we could call W10 a Unix desktop. Is that allowed?)
> "the hope that Apple would purchase or license BeOS as a replacement for its aging Classic Mac OS.[4] Apple CEO Gil Amelio started negotiations to buy Be Inc., but negotiations stalled when Be CEO Jean-Louis Gassée wanted $300 million;[5] Apple was unwilling to offer any more than $125 million. Apple's board of directors decided NeXTSTEP was a better choice and purchased NeXT in 1996 for $429 million, bringing back Apple co-founder Steve Jobs.[6]"
What a different world we'd be in if Jobs had stayed at NeXT.
Assuming Apple would managed not to close doors and achieve a similar success with BeOS, the FOSS UNIX guys would have had to contend with GNU/Linux and *BSD as desktop alternatives to BeOS and Windows.
NeXTStep would have probably closed doors as they were already trying to survive by ditching hardware and selling OpenSTEP instead.
Which Sun played for a while, but decided to not adopt it in the end.
BeOS IMHO would be pretty unstoppable right now, had Apple adopted it, certainly much better/more modern than the current OS X. They should have offered $200 mil to Gassée, and brought Jobs in with a bonus of some sort, and still paid out less than they did. (Although I suppose Jobs wouldn't be enthused to work on BeOS.)
No user isolation on a single-user machine, via type safe languages, was already done in Xerox PARC workstation written in Mesa/Cedar.
Actually had Apple adopted BeOS and succeeded in doing that, there wouldn't be any major UNIX desktop to talk about.