I work for a large consulting company that does work all around the world. From what I've seen, the midwest appears to have a pretty heavy use of .NET and other Microsoft technologies. Very large banking and insurance companies moving their .NET code bases to Azure. As you move further to the coasts, AWS takes over more as the cloud provider of choice for most enterprises and you see a lot more Java. Right now I'm looking for .NET + Azure architects in Iowa, Nebraska, Minnesota, Kansas and Illinois.
I can think of a lot of reasons why companies and startups would find it bad for their use cases tbh. It's hamstrung by microsoft licensing and ecosystem, and while building tools for enterprisey stuff is great, web-style startups are more of the focus here.