Just a bit correction there. SCO-Linux litigation is pretty contemporary. Way back before then, there was the System-V vs BSD "Unix wars" ( https://en.wikipedia.org/wiki/Unix_wars )
SCO-Linux litigation was just the SCO assholes wanting to get a piece of the pie when they were dying out.
[0] https://www.cnet.com/news/sco-leaked-e-mail-a-misunderstandi...
The Day SunOS Died
"Bye, bye, SunOS 4.1.3!
ATT System V has replaced BSD.
You can cling to the standards of the industry
But only if you pay the right fee --
Only if you pay the right fee . . ."
For context, the guy who wrote "The Worst Job in the World" email was Michael Tiemann, one of "open source's great explainers." ;) Now he's pranking IBM executives by installing RedHat Enterprise Linux on their mainframes.