Haskell is and has always been primarily a research language. It just has some popularity outside the academia. This is something everybody investing into Haskell knows (or should know).
That's not what the author of the article seems to think, though. He admits that "Haskell is never really going to be a mainstream programming language," but even non-mainstream languages, like, say, Erlang or Clojure are very much concerned with the why, and aren't aimed at research. A research language and a non-mainstream language are two very different things.