It's really more of a result of human sentiment than anything. F# is underrated and underappreciated, and it just doesn't have a critical mass of people developing libraries for it. The issues to its adoption were being associated with .NET (Windows-only at the time) and Microsoft and being sold as a C# alternative rather than its own thing and an alternative to other languages like Python.

An interesting thought experiment is to think if someone was to release F# today as a new language but calling it something else, like Flosure or something. I bet people would lose their minds over it.