Regarding the true Unix, there was also Unixware, which was AT&T's effort to move Unix to PCs (with Novell). It later passed on to SCO before they were sold, restructured, renamed and rebranded and subsequently became lunatics, In the end it seems like they offloaded it so some other company that's just letting it die.
It was a good system. Not super fun, but industrial strength server stuff that was really reliable. Bit of a shame.
But of course, Linux was just simpler for everyone, it just doesn't make sense to keep a million proprietary systems.