Well for that matter so does Clojure, and both have had a while to pick up traction. Do you think it'll be easier to solve the primarily-social problem of getting traction for languages like that (and I say this as someone who adores Clojure and has some affection for Haskell) or to solve the primarily-technical problem of figuring out chip technologies where one can metaphorically jack up current software and slide the new chip technology in underneath?