I’ve often thought that would be true for niche languages. I interviewed at a fintech whose backend is written in Haskell, and definitely got that vibe from the interviewers.
I worked at a company that hired like this. On the whole it was good, but it wasn’t a panacea. A surprising number ended up being academic types that were extremely smart but could never actually finish anything. Amazing guys to talk to at lunch though!
As a startup CTO currently building with Elixir, I can say that it's absolutely possible to hire people who know how to deliver. I completely agree with the parent comment re: self-selecting people who write code as craft. I've put together an excellent team of developers who deeply care about what they do and are focused on shipping.
Why isn't it used? It's niche and betting on such a small community is risky for the majority of companies. Why use Elixir when you could hire 10 engineers to pump out javascript. That's the mentality of most.
Hiring for elixir was great, it self selected people who wrote code as their craft. You kind of have to be curious about code to even be aware of Elixir, know how to write elixir. These types of devs would pick it up really quickly because the language is just so damn ergonomic.
I'm using Elixir now, and I wake up so happy that I get paid to do this. I am really blessed.