Well, you usually don't choose languages based on their technical merits, but rather on the ecosystems around them. These depend on popularity which you get by having traction, which you get by being quickly productive. This is why very tolerant or very familiar languages succeed. Being chosen as one of the blessed languages that are taught in universities is also, of course, priceless. A killer framework (Hello, Ruby) can also do wonders.

Not that this defends the very poor syntactical choices that Lisp and Haskell and their communities have done (minimal grammar is not a good thing! One-symbol names are horrible!), but a lack of popularity is not as damning as it sounds.