You can if they are motivated to learn. Unless you are offering Jane Street levels of compensation; and in return, the candidate is willing to believe, or pretend to believe that company's shtick about OCaml being so categorically superior as a general-purpose development language so as to leave all the others in the dust -- most likely they won't be.
OK, I'll grant that if you have that "magic skill" then you can in fact recruit developers for niche languages.
Most companies don't, as we know, and frankly it's amazing to me how incoherent their communications are throughout their so-called hiring process.
https://www.benjamistan.tech/2022/06/26/wasting-time-in-tech...
You pick one regardless of language. Not sure what's your point here.
I would like to confirm that fact, by comparing productive output..
'Producing code' to measure 'superiority' is about as useful a metric as counting lines of code to measure productivity.