Proportional to its number of users, Common Lisp probably has more libraries than any other language in history. The problem is described in the article: all of the libraries are half-baked "trivial" implementations that cover the author's use case. Very few, if any, CL libraries are continuously maintained. Even fewer have usable documentation. Fewer still are feature complete.
And yet, the last time I attempted to write a trivial GUI application using GTK and CL, I could not find a single usable library. I tried four and they were all unusably broken on my platform. (This was some years ago. Clearly at least four more implementations have come around since then.)
I think this is a step in the right direction. If the XKCD comic is true that every generation produces a handful of lisp hackers, I hope this is the generation that looks to Quicklisp as a foundation to build a modern, consolidated set of batteries.
Check out the list of EIGHT GTK+ bindings for Common Lisp: http://www.cliki.net/GTK%20binding
And yet, the last time I attempted to write a trivial GUI application using GTK and CL, I could not find a single usable library. I tried four and they were all unusably broken on my platform. (This was some years ago. Clearly at least four more implementations have come around since then.)