Comment by da_chicken

Yes, developers used to like Microsoft. That was where all the money was, and Visual Studio was an extremely good IDE in the late 90s and early 2000s. And at the time, Microsoft's documentation was the best. C++, VB, and then .Net development combined with Sql Server (then a budget option) was a very enticing stack. Using ASP instead of Perl or ColdFusion or PHP was also attractive.

At the time Mac was still largely dominated by PowerPC and Classic OS. And Linux was still seen as an OS for hobbyists and universities. It was not taken seriously until well into the 00s and the 2.4 kernel. Sun was struggling with Java, and the unices were well into their decline from the 80s.

I would say that the transition was how much better Apache was than IIS when it came to operational and security issues.