Reference counting still requires you to keep track of cycles. Also performance is less than GC, especially in multithreaded environments. And Swift is not a serious language outside apple ecosystem.

OCaml is actually very good language. I hate how people outright dismiss it mentioning multicore. Neither JS nor Python have great multicore story. And most applications don't need multicore.

Wish there was a good static compilation toolchain for .net core. F# would gain much more traction then.