However, MS and IBM were already getting "divorced", and this may have been a token part of the settlement. A year later, MS shipped Windows NT.
The OS/2 interregnum was quite long. All those years Microsoft was still selling their 16-bit OS/2 1.3 because their server software (including SQL Server) ran on that platform.
Microsoft and IBM had a joint development agreement for many years. When they "divorced" in 1992, they both retained rights to DOS 5, Windows 3.0, and OS/2 2.0.
Microsoft had NT, which was a multiuser system, unlike OS/2. Plus it had an OS/2 1.3 layer, specifically so you could migrate SQL Server. So after the divorce, MS obviously didn't promote OS/2, because they had a better thing coming.
There were 3 editions of OS/2 planned:
OS/2 1.x, 16-bit, for the 80286
OS/2 2.x, 32-bit, for the 80386
OS/2 3.x, portable, for RISC and other CPU families
When MS and IBM split, IBM kept 2.x and Microsoft got 3.x.
It hired Dave Cutler and his team from DEC and gave them OS/2 3.x to complete. It was built on the Intel i860 RISC CPU, codenamed N-Ten. So this version was codenamed OS/2 NT.
Windows 3 was a big hit and Windows 3.1 even bigger, so OS/2 NT was renamed Windows NT.
Much of the world still runs it.
My recollection from interview was ... he didn't like it (OS/2), and built their own OS arch from scratch but with some OS/2 back-compat to fulfill contractual obligations.
[0] https://www.itprotoday.com/windows-client/windows-nt-and-vms...
That's not where the name comes from, but it's kind of funny.