Which platform is that? Windows? .NET? It's perfectly possible to target both without using Visual Studio. Microsoft has somehow[0] convinced people that using VS makes their lives easier. Lots of people pay for IntelliJ too. I think the trick here is to get people hooked on languages that have a lot of boilerplate and therefore require a powerful IDE to be usable, then sell people the IDE.
[0]Based on personal conversations with individual VS users, it actually appears that VS is what many developers want or think they want, not just something forced on them by management.
No, I wrote exactly what I meant. As others have pointed out you can use many other free tools, or even free versions of Visual Studio itself.
People pay absurd money (up to $10k per seat) for Team Edition which provides entire enterprise developer/tester/database/architect/team workflow instead of just IDE.
If you build something truly valuable people will pay, so long as they have the money. Like I said, the trick is to find the right people.
First, many of the enterprises don't pay all that much for Visual Studio. And, having previously been in the compiler business, I don't think very many compiler producers make any money at that game. If you could see the internal cost numbers for what it takes to put Visual Studio together and to maintain it, it would be hard to see how they could anywhere near profit from it. Back in the day, there was a report that they had 50 programmers on the C++ compiler alone.
Perhaps Walter Bright can make money writing compilers, but that would be an exception. I think that you will find that compilers and other language tools are sold in conjunction with something else.
The trick is to pick the right customers.