They just had the advantage of having the only viable GUI-based OS on mass market computers. Linux has only begun to be usable on the desktop around 2005-ish, Mac always was expensive because you had to buy Macs.
In 1995 the Windows GUI was complete trash The Linux GUI much better.
I was the sole Linux guy (Microsoft Windows 95 mostly plus a HP Unix workstation the boss controlled fromOS/2 desktop). The windows machine constantly crashed and ran like a steam roller in two feet of mud. Lots of mess, not much speed.
It was not the quality of the operating system that made Microsoft successful. They were successful despite having the worst operating system in that room. Significantly worse.
* Backward compatibility: Ripping out everything and starting over is very expensive; what is the return on this investment for the company's bottom line?
* Applications: Everything in business, perhaps outside creative arts, is compatible with Windows; much is only compatible with Windows.
* Management: Active Directory is by far the leading tool for managing thousands of computers efficiently. That has a network effect: Other management tools, including for specific applications, integrate with AD. This automation greatly reduces labor costs and improves quality.
