Running on Linux doesn't tell us much in itself. Can it compete with long-established alternatives on that platform? Does it have adoption? I think the answer to both these questions is a strong no.
From my personal perspective, roughly 75% of all applicable (non-Windows-UI) .NET greenfield project go straight on Linux. The brownfield/maintenance situation is surely different. Companies are not married to the Windows stack when you get the alternative for free. And R&Ds just follow that.
.NET is on Linux and performs excellent there.
(FWIW, I spend about 40% of my working time dealing with dotnet).
There are scores of Windows developers who’s skills are now transferable to Linux, Apple, and Android development (albeit with some caveats).
Thank you, Microsoft, for showing me a way out.
Many Linux people like to use Python, for instance. Unfortunately, it's a slow language for all sorts of incidental but hard-to-fix reasons. This has led people to look for alternatives. I think Go is increasingly used as an alternative, but it lacks features like operator overloading which are a necessity in certain areas. There's JVM languages like Java, Kotlin and Scala as well. Nim is up-and-coming. Some people use functional languages like Haskell and Common Lisp. C++ is widely used but not much loved.
I realize of course that not all Linux users are C programmers.
Given the opportunity to transfer my C# knowledge over to Linux, I'll take it.
Since we are on the topic of Linux so something exciting was merged for .Net6 that wasn't talked about; the new file interface with support for symbolic links. That sounds a bit absurd but it's been a long standing issue with challenges you wouldn't expect..