Remember, Lisp is at least a 50-year language, and Lisp was originally created as a joke or a teaching example or something. The great bearded wonder, the one that Lisp guys make shirts of, Schultz or McCarthy or whatever his name was, only wrote up the spec to make a point, some kind of math thing iirc, and somebody egged him on and they ended up implementing it. But it wasn't that he just had this magic ability to build a great language. He made a thousand other snarky points in his life, and this one just happened to be so well phrased, mathematically, that it trumps all other languages, in the opinion of many people. That's not a one-time stroke of luck in the language design department; it's the results of decades honing his craft as a master of snark.
That sounds a bit simple. What about that other great bearded wonder, Leonardo? He only made about 30 paintings.
http://en.wikipedia.org/wiki/List_of_paintings_by_Leonardo_d...
I know it was a cheap shot but I couldn't help but laugh when I got to that point in the article. The relative lack of activity on http://arclanguage.org/forum makes me think the best reason to choose Arc at this point is to run news.arc.