We have access to millions of libraries. I look at BEAM languages and OCaml every once in a while but can’t quite drag myself over there, knowing that in .NET, just as an example, I can choose between a dozen JSON serialisation libraries that have been optimised and tuned comprehensively for decades.

But then, those libraries are also our curse. If you consume them, everything is OO so you either give up on functional purity and start writing imperative F# code, or you have to spend time writing and maintaining a F# idiomatic wrapper around it.

Similarly I was working recently on project to develop a library which was going to have downstream consumers. The problem lent itself really well to domain modelling in F#. But I knew that my downstream users would be C# devs. I could invest the time and write my library as “functional core, imperative shell”. But then I decided that since the interface would be OO anyway, I might as well just write it in C#.

Thankfully what keeps F# going is the wonderful community around it, not Microsoft. I know some people (outside of Microsoft) have worked on a standalone F# compiler but it’s still very early stages. Maybe one day.