Though that doesn’t mean they’ll be more productive, and then adds hiring challenges. So the break-even is not simple.
One of pg’s early essays was on exactly that subject (“the python paradox).
The code is all Scala, but written by a bunch of ex-Java devs. I have made attempts at education, and the code is improving, but the fundamental structure of the services are bad, and there is still a lot of bad code. I am not saying this as a FP purist, some of the code would be bad by the standards of Java programming.
Bad programmers then hire other bad programmers. Because it is hard to find experienced Scala developers, they have brought in people with java experience, or big data Python programmers who claim to have some experience using Scala with Spark. I am now involved in the hiring process, and it is slow and dismal. To be fair, the kind of contractors this company hires are mediocre, regardless of language.
The features of Scala create novel ways for confused programmers to screw up, and we aren't even doing anything esoteric, like pure FP. I suspect there are some similar traps in Clojure.
When it was released, there were two camps to adopt it: people that wanted an FP, and people that wanted a better Java. Since Java went through a long period of stagnation, most of the Scala code out there is written by Java developers that just wanted a better Java.
Kotlin has stepped in and replaced Scala for "better Java" role. But this history has left a pile of crap code written by people who didn't want to use Scala.
Clojure doesn't have this problem because you couldn't ever use it as just a better version of Java.
However I wouldn't mind coding in Scala. I like OO, I like FP, I'm comfortable with expression based programming and immutability. Based on that alone - and playing with Scala in my spare time - I feel like someone with my background may be more suited than someone with a commercial Java "mutate every variable" background.
But I'd never get through your filters.
I’ve been happily coding (and hiring) in Python for the last four years or so. Still doing Rust and some Scala at home where deadlines don’t exist and hiring is a non-issue.