I don't dispute it has niches where it does well, or at least "works". The implication often given is general purpose productivity superiority.
There are also a bunch of examples where Lisp was used to prototype or for rapid application development. This enables exploring ideas or conquering early markets. Later iterations may then reimplement the thing... That's another model and is also fine - though there are projects which had not much experience and were not able to get the thing off the ground. For example the first version of the Postgres database was written in a mix of some Lisp implementation and C. This did not work well for them and they switched early away from Lisp. Similar the first version of Reddit was written in Lisp, but it did not really work that well for them and they switched to Python.
> The implication often given is general purpose productivity superiority
I don't think that claim makes sense in general. Much of the productivity in modern software development does not come from the programming language. Much more important nowadays is the general eco-system.
For example it makes very little sense to develop apps for iOS in Clojure, since there is zero support for it from Apple. Thus most iOS applications are written in Objective-C and/or Swift. An assumed 'general productivity superiority' doesn't help at all to compensate the total lack of platform support from the platform provider.
I meant for "general" programming. I apologize for not wording it clearer earlier.
Re: There are also a bunch of examples where Lisp was used to prototype or for rapid application development.
Yes, this is a niche it often does well in. It's partly how Paul Graham beat competitors in the store app arena.
The post you responded to specifically used Java as an example, though. Clojure specifically is clearly targeted as an alternative to writing raw Java. A number of other languages rushed in to compete for that space, and while Scala and Kotlin seem to be more popular than Clojure, I have to admit the only JVM app I actually rely on now, uses Clojure.
Puppetdb, specifically. Puppet is a ruby project, but the database component is written in Clojure. I dislike Puppet for many reasons (syntax, coupling, architecture), but not because of its database backend.