The thing is, core.typed is a really powerful type system, but the ergonomics with the way Clojure works didn't work out, so people prefer not to use it when developing with Clojure.

That's what I find interesting about it. Not all language benefit from a type system in the same ways, some, like Clojure, actually get crippled. Now, it can mean that you need to find the right kind of type checker that provides the correct ergonomics for Clojure and maybe that would work. But it's still quite interesting.

For example, Erlang has a bit of a similar thing, Dyalizer made specific choices to work within Erlang's design. Had it not done so, it probably wouldn't have found adoption. Same with TypeScript.

So what's interesting here is that you have an apples to apples comparison where a language is found to be better without the constraints of static type checking.

When you look at other statically typed languages, they're oftened designed around the static type checker. That's the main focus, and the language itself revolves around that. So obviously in such a language, the type checker would be a necessity, as it's the main draw. So it's interesting to look at Clojure for a counter example.

That said, JavaScript you could argue is also an apples to apples comparison, and people opted for types. It'll be interesting to see also where Ruby and Python go, now that they have type checking features as well.