[stevesimmons]

There's productivity at the level of an individual developer, and productivity at the level of an enterprise.

Just because an individual or a small team can be highly productive in say, Haskell, doesn't mean it makes sense for the whole company.

In Finance, the area I work in, the only FP success stories that come immediately to mind are a couple of teams at Standard Chartered for Haskell, and Jane Street Capital for OCaml. And they are notable for their rarity, not because there are plenty of other comparable examples.