Countering the Ministry of Truth
Back in 1989 The _Microsoft_ OS/2 2.0 developer kit was $2600. That was the official dev kit for both the IBM and Microsoft developer community.
In 1990, just before the 'divorce' MS was still encouraging developers to target OS/2 2.x and showing previews of OS/2 NT [written in C instead of assembler was it's big feature]. WordPerfect was one of the companies caught in the trap, investing in a native OS/2 version.
In 1991, IBM's OS/2 developer kit was part of a $100 / year annual subscription - and several third party compilers were released.
In 1992 Microsoft's version of OS/2 still had the old program manager / file manager interface, looking just like Windows 2.1 or MS OS/2 1.2
Also in 1992, IBM released their OS/2 2.0 [on 26 floppies] featuring the document oriented 'Workplace Shell'
In 1993 Microsoft renamed the OS/2 3.0 project to Windows NT, and also stated it was a fashionable 'microkernal' based OS. The promise of multiple API personalities had Bill the Gates proclaim "NT is UNIX, in six months it will be the most popular UNIX'. Needless to say, NT was not and is not UNIX [even the fossil POSIX subset api layer has been deleted]