Probably for the exact same reason each year you think about learning OCaml you decide not to (I mean this sincerely, not trying to be snide).
I think the main reasons it doesn't see mass adoption in industry:
* There are only two major companies that do a substantial amount of OCaml that I can think of off the top of my head, Jane Street and Ahrefs. Facebook does some OCaml too but I don't think it's a core part of their stack.
* The tooling is lacking.
* People have an easier time learning Python or Java so you'll have a larger pool of candidates if you use one of those languages.