[CmonDev]

"You'll still get the HUGE bump in development times (due to the inherent expressiveness of the languages)"

Not sure if that is true. Maybe for small typical web-projects or server-side scenarios that benefit from thin scripting layer (like at Google). If it is true though, then Haskell and OCAML/F# would be even better because you get expressiveness without loosing the obvious advantages of strong static type systems.

[VeejayRampay]

Those language are too cryptic for people to adopt them en masse.

There's a reason why Ruby/PHP/Python are so pervasive, 95% of people simply do NOT care about monads and poly-variadic fix-point combinators for mutual recursion.