I'm not sure what you mean by "never took off" but thousands of developers around the world, myself included, have made their living just writing Clojure code for many years. So, it has certainly taken off for them. And there are many, many companies using it all over the world. I live in a town of about half a million people, so not super big, and there are about 12 companies primarily operating on a Clojure codebase.