If you mean the overall Lisp family, I think it's more clearly on an upward swing, especially due to Clojure's popularity (and if you're willing to stretch, Julia smuggles a Lisp-like language under cover of Matlab-like syntax).
cll was rabidly against OSS, e.g. Pitman's pure hatred for it was practically Gospel there.
A few years ago some younger Lispers emerged, for who OSS was natural, just like with the short Ada renaissance.
At least the "young Lispers" are still there, unlike their Ada counterparts, even if they haven't taken over the world.