I heard somebody make a similar argument one time in regards to Common Lisp. He said that with Java you would have to wait several years sometimes to get a feature (assuming the language developers actually cared about the feature), but with Lisp, you could just implement the feature yourself. I've always felt this is one of the strongest arguments for using a lisp-style language.
Edit: this is possible too in languages like Elixer and Ruby using macros, but eventually the readability suffers and debugging complex macros in those languages can be a nightmare.
Edit: this is possible too in languages like Elixer and Ruby using macros, but eventually the readability suffers and debugging complex macros in those languages can be a nightmare.