I don't think anyone is saying Clojure is better than Python in the abstract. Clojure has a different style from Python and that style can be more fun and is better for some specific tasks like application programming and anything that wants to use multiple CPU cores. Tends to have better long term prospects too, old Python code doesn't work in my experience but things on the JVM have cockroach powers.

As for why things are and aren't popular, who knows? It is quite possible that people just don't like the look of the parenthesis, or there are a couple of key libraries that aren't good but nobody vocal has put there finger on which ones. The error messaging isn't quite up to a standard that people want to deal with. Or maybe popularity is really just about pure random chance, at most 4 languages get to have >20% market share, by definition.