> The biggest thing Linux had going for it in terms of winning market share was running on commodity x86 parts in a time period when the commercial Unices weren't touching it
From the 1980s to 1993 there were:
v7 ports: Microsoft Xenix (later became SCO), Venix, Coherent
System III ports: PC/IX (later 386/ix)
SVR3 ports: official Intel, ESIX from Everex
SVR4 ports: Dell UNIX, Novell UnixWare, Microport
Strictly speaking, Coherent wasn't a V7 port – they wrote the code from scratch rather than using any of AT&T's code, and they never paid AT&T any Unix license fees.
AT&T was suspicious, but even after a careful investigation by Dennis Ritchie himself, they couldn't prove any of their code had been copied.
Given both the V7 source code and Coherent source code have now been released, you can compare them yourself and form your own opinion, if you'd like.
Microsoft abandoned Xenix when AT&T decided to commercialize Unix with SVR4.
OS/2 was, in fact, created to be Microsoft's Xenix replacement (and then when Microsoft fell out with IBM, we got NT as Xenix's replacement's replacement).
"Microsoft abandoned Xenix when AT&T decided to commercialize Unix with SVR4."
They not only kept supporting it via SCO Group but even used that company to bankroll an attempt to kill Linux in court. IBM, dependent on Linux, promised a billion dollar battle. Company eventually went bankrupt but its "real UNIX" is still in use by Fortune 500 companies as legacy systems. That they sold inventory-management solutions on top of SCO Server means quite a few are mission-critical. That money coming in is probably why they keep fighting over whether it should stay bankrupt or not.
Okay? Red Hat Enterprise Linux wasn't released until 2000, so I don't know what Microsoft's late-80s UNIX distribution has to do with it. Google was running Linux from the early days, and they launched in 1998, which is nearly a decade after Xenix stopped being updated.
EDIT: Yes, Linux has its origins sooner, and if you want to know why Linux beat the BSDs to mindshare, what was going on in 1993 is very important. But Linux wasn't competing for mindshare with Xenix, it was stuff like Solaris (which did have an x86 port, but was mostly running on SPARC), AIX (which was mostly IBM big-iron and POWER), HP-UX (which was PA-RISC and IA-64), etc.
If you want to talk about post-1993, saying that Linux won because there weren't any commercial x86 Unices makes even less sense. Xenix did not stop being updated, it became SCO UNIX. SCO bought and continued to sell UnixWare from Novell in 1995. x86 Solaris came out in 1993, but Sun actually had an x86 Unix since 1991 when they bought ISC.
From the 1980s to 1993 there were: