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.
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).