There are a great many companies and developers in the .NET orbit.
I agree there is still a certain bifurcation between the Microsoft and traditional FOSS worlds in terms of conferences etc. But I'm not sure either needs to convert the other.
The stigma that many UNIX circles still think .NET is Windows only, and will describe you .NET Framework as the current .NET.
Quite common in many circles that haven't kept up with .NET, nor are the kind of people to waste their lives in places like HN, Reddit, or spend evenings and weekends coding the next great app in Github.
Many of these people do hold management positions, and will favour non-M$ technologies for their company.
Yes I wrote M$ on purpose to stress the company culture.
There are a great many companies and developers in the .NET orbit.
I agree there is still a certain bifurcation between the Microsoft and traditional FOSS worlds in terms of conferences etc. But I'm not sure either needs to convert the other.