Surely everyone experienced at these competitions would quickly figure out that lisp et al are huge competitive advantages, and everyone would quickly switch.
From what I've seen working with some living legends in computer science the language makes almost no difference in actual productivity, it's just personal preference.
It's just trading one performance characteristic for another. Every language has it's sweet spot, and if you know them you are just as productive in that as another.
If you aren't productive in a specific language, you are doing it wrong.