At least P. Norvig things python is an acceptable language, if not LISP. I think the point about being optimized for small teams is a significant one. Also, because LISP appeals mostly to programmers, but it often "repeals" people with expert knowledge (e.g. scientists without a strong programming background). P. Norvig mentioned that when he converted his AI book from Lisp to python code examples, it seemed much more natural to most people,