Clojure never had a "shot to become a popular general-purpose language". That was never its goal. Popularity is not a useful measure of whether something is actually good technology.

Clojure is designed to solve hard problems, for people who want something objectively "better" than mainstream tools. That's why it tends to attract more senior developers -- people who've felt the pain of other languages and want something better -- although we also see a steady stream of new developers who are interested in better tools even before they've felt that pain.

Of course it's niche -- it's a Lisp! It's alien. It's "too different" for many companies or many developers to even consider it. And that's fine. The space is big enough for niche languages to thrive and for developers to build careers on them, if they wish to do so.