I am not doubting that Lisp is a language with which can be used to write succesful commercial applications. I am questioning the claim that it is vastly more productive for commercial applications. Of course it is not really possible to say how somebody else in a different language would have needed, so maybe a compromise would be to see some 'magical'lisp code examples.

ITA software would definitely be worth looking at, but you would need to get hired by the right team.

More details here http://www.paulgraham.com/carl.html you can also glean more information by searching over older discussions about ITA on HN.

This is really interesting. I am amazed by the circumvention of the GC for large data; this thought would have never occured to me.