The split between the Reason and BuckleScript/ReScript dealt, I believe, a fatal blow to both communities which were now split. It's a shame, I could have seen Reason in the same space as Rust, an ML-like language (well, literally an ML via OCaml) except without a borrow checker. It would have been great to use it in place of TypeScript on both the server and client, but now ReScript is incompatible with Reason, by design.