> You have to be really incompetent to write a typical Java service in a way where it is no longer possible to develop it at all

I've seen multiple Java services reach this state and require complete rewrite as the only path forward. I think you've just had one kind of experience and are making conclusions out of it, but in your case, I don't think the programming language is a factor. You just happened to see some failed Clojure projects, as I happen to have seen failed Java projects.