The problem is F# has arguably the best tool chain out of all of the languages you listed. Hell, I still have problems getting Scala to work with Netbeans 7.1 and I'm not sure of any IDE (for windows at least) for ML, Haskell or OCaml.
You may be right, but on the other hand F#'s toolchain isn't that hot on OS X and Linux (being facetious, but I'm half-serious). Anyway I was really only talking about the presence of a "first-class" REPL.
