Or Haskell is just too different from what most programmers are familiar with. It's not really Go versus Haskell, It's Haskell/Ocaml/ML/Lisp versus mainstream languages.

It's also not like Go is the only popular language. Other popular languages like Javascript, C# or Python have plenty of features and magic. Also, Elixir seems to be doing pretty well, so maybe that's a way for functional languages to gain traction.

Elixir, being newer, was made with modern environments and tooling in mind. Go has the same advantage.