I don't worry about Clojure's future either. I think it'll stay strong for at least another ten years, and it's hard to see beyond that for any language. I use it professionally, and would strongly consider it if I was founding a startup.

But as you say, it's popular "for a Lisp dialect" and I don't expect it to reach past that. I would love to be proven wrong.

That being said, your post made me realize that instead of lamenting the nicheness of Lisps, I should be encouraging other people to give Clojure a shot. And not only to help Clojure be more successful, but also to bring a little bit of joy to their daily life like Clojure often does. (It sounds trite but it's true.)