I may be wrong, but I think the parent poster was talking more about the language and ecosystem than the community. I, too, have found the community to be amazing. But the language itself used to be quite frustrating to learn. It's better now, but I think that by the time it got fixed many companies and teams had already been burned.

Clojure is particularly vulnerable to that because it really is an enterprise applications language. That makes it more vulnerable to learning curve problems than a language like Rust whose most direct competitors are other languages with comparably steep learning curves.