Re: some pretty good products
NT was not based on OS/2. It was meant to be OS/2 v3, but has little similarity to it. Yes, it shipped with HPFS until v3.5, but that was written by Gordon Letwin of Microsoft. The OS/2 subsystem was required to run MS Mail until Exchange reached maturity.
(There was also an OS/2 1.3 PM subsystem for NT. If anyone has a copy of this, I would be very, very interested to see it, as I'm not aware of anyone who has it, never mind screenshots).
Dave Cutler came from DEC, NT is more derived on a DEC system called Prism.
The first release of NT was v3.1, not 3.5. It was memory hungry for the time, but not too bad. I ran OS/2 for preference during the 90s, but NT3.1 was probably in a better state than the initial release of OS/2 2.0.
The issue with NT 4 was not so much the desktop (that was needed, it looked embarrassing next to OS/2, or even '95), but the fact graphics drivers were moved into the kernel. However, it may have been needed, by 1999 the lack of USB and DirectX in NT was a real issue if you wanted to run more than servers. By the mid nineties the separation of desktop/server operating systems was ending, it was rapidly apparent that Netware would not survive, and that NT would eventually be the future.