Re: what a lot of people..
@boltar. OS/2 was only at 1.3 when Windows 3 came out and it was still a joint IBM/Microsoft gig. The relationship broke up later. As for whether Windows 3 was a knock off, you'll find that pre 1.3, the interface and some of the code (for compatibility) in OS/2 was lifted from Windows.
What lost it for IBM was expense and lack of hardware support compared to Windows. As for MacOS, it was a well packaged amalgam of existing ideas, as most Apple products are (not actually a crticism). MacOS was too wedded to expensive, proprietary Apple hardware (similarly, so were Commodore Amiga and Atari ST, though less expensive - they just didn't evolve either), hence the proliferation of Windows - hardly Microsoft's fault that the competition were inept.
As for servers, well you need to blame the Traditional Unix vendors and Novell. The likes of SCO were too busy looking at the monster solution market and overly complex systems. Novell scuppered themselves with licensing and a lack of application support. Microsoft's NT effort had merit in concept in that it was an easy to use platform that could do authentication and networking, but also could still provide a flexible application platform and scale sufficient for SMEs. NT's issues were in execution, not concept. Again, competitors were inept in reading the market and again, not Microsoft's fault.