I have just finished reading a very interesting post from Tim Sweeney
While I don't necessarily agree with him regarding the adoption of ML (OCAML / SML / F#) and haskell, I think the salient point he makes is that, in all likelihood LISP will outlive all the popular languages of today. That is not to say that LISP will become the hundred year language, merely that it will still have an enthusiastic user base long after C++ and Java et al are pushing up daisies.
What is it about LISP that is so compelling. They say that unless you have used it you will never know, and that once you have used it you will become a better programmer, regardless of language. From my own experience I would say that their is some truth to this; the barrier to adoption really comes down to syntax. Just as with Haskell, Erlang and OCaml, the syntax does not conform to the majority dialect and therefore faces an up hill battle for wide scale adoption.
This is one of the reasons that Dylan, despite its banishment from Apple, continues to peaks my interest. Its difficult to see a future for Dylan, but every time I decide to move on I find myself drawn back into the fold.
I think with a concerted effort, perhaps a carbon / cocoa back end for DUIM and a Dylan port of Uncommon Web, there may yet be traction. By the way, who is the patron saint of lost causes.