I can add F# projects to existing solutions and use F# in some places, C# in others, and C++ in still others, heck even VB.NET can come by for a drink if I'm feeling shameless and not needing to keep up appearances.
OCaml cannot do that. I say this as someone who currently is finishing a year of F# study with plans to study Rust in 2020 and OCaml in 2021.
They could have ported ocaml to the clr instead of doing their own ms thing. They could have promoted ocaml instead of splitting the community interested in a practical ml derived language - with the consequence that today neither has a relevant user base.
OCaml cannot do that. I say this as someone who currently is finishing a year of F# study with plans to study Rust in 2020 and OCaml in 2021.