OCaml has many (almost all) of the advantages that you attributed to the other languages, and adds many more besides. What makes them 'killer features' for those languages but not for OCaml?
Nothing really, but they are mainstream languages and OCaml is (currently) not. So if you really need one of those then there is already a more widely adopted option that gives it to you. It's not that OCaml is bad (I like it a lot) it's that to adopt it you need a really compelling reason to do so.