They are, but I don't know many C# and VB developers who aren't also using JavaScript. Just flogging your enterprise apps together in WinForms isn't so viable now that people want to be able to use MacBooks at work, too.
Javascript is useful for websites. And outside of the tech bubble, that's basically all it's good for.
Yes, you can use Javascript for non-website stuff. But nobody is doing that because there are many cheaper and more efficient languages out there for doing all that other stuff.
I can only imagine there's a ton of massive ASP.NET MVC + a bit of jQuery internal apps still chugging along too