Most ordinary shops are just better off avoiding these stacks altogether. They don't really all that much compared to your C based languages. And its pointless to keep your hiring pool small.
There is also a steep learning and onboarding curve to climb when you onboard new employees. Significantly low help when you face issues, and just overall lack of help and information when you are stuck in a non-trivial issue. This is not just with F# or OCaml, but with all non-C based languages.
Only reason hedge funds can continue using this is they can pay people to suffer through this.