The good haskellers I've talked to about this say Haskell has only recently become a mature language=) The modern fast data structures packages date from 2007

The good haskellers I've talked to about this say Haskell has only recently become a mature language=) The modern fast data structures packages date from 2007 to 2011 (containers, vector, text, and unordered-containers). Recently there have been more breakthroughs like FB adoption and an unrivaled web API library in Servant (https://haskell-servant.readthedocs.io/ https://haskell-servant.readthedocs.io/). Also we got Stackage and Stack recently (which ended "cabal hell"). Even "cabal hell" is gone with the new cabal-install improvements. So don't count Haskell out too easily because it's old. It's an awesome language, but it took people a long time to figure out how to program well in it, given that it's so different from the normal way of doing things.