Your comment makes me think the kind of people who favor OCaml over Rust wouldn't necessarily value a huge ecosystem or the most advanced tooling. They're the kind who value the elegance aspect above almost all else, and prefer to build things from the ground up, using no more than a handful of libraries and a very basic build procedure.

Yeah, I was that kind of person, then I wrote a real tool that does real work in OCaml... and then I discovered than I am no longer such a person and went to Rust.