As for Scala it's pretty much a dead language, no one work with it and it's impossible to find dev for it.
10 years ago I was moving Scala code back to regular Java.
go and kotlin aren't it, gleam scratches the itch but I can't justify writing code that would impossible to hire for.
scala situation is a real shame.
I think it used to be common to just look for smart people and assume they can run with whatever stack. Wasn't that the point of abstract algorithm questions etc. (basically an IQ test)?
Lots of companies where software isn't the focus see it as a cost center, so they'd prefer to hire lower-IQ specialists instead of higher-IQ generalists, because the latter are more expensive/have more options.
I worked on a purely functional Scala codebase (Cats). I joined after the original authors were gone.
Some new comers were not fluent in it after ~a year.
The whole go team's philosophy tends to also revolve around assuming their users don't know what they're doing, which is annoying. Like an inline keyword: thinking you know better than me doesn't mean I'm not going to inline it; it means I'm going to manually write it inline myself in the code, and then think the language sucks because it's tedious, error-prone, and verbose. Or they tend to mark lots of stuff private for no reason, and e.g. with TLS 1.3 they just ignore your config because they think they know better, etc.
Java tooling taking up a lot of ram was a major motivation for me. I have done a lot of Scala as well. I don't think either Java or Scala in the real world beat go on performance for most cases. I don't doubt that in some cases jvm can do better but at least before Valhalla delivers all the promises, in real world, I am doubtful.
I have been a Java/Scala user almost for the majority of my career. I doubt I would pick jvm over golang going forward though. Also not having to deal with OOP is a plus.
Not sure which dev tools specifically you're referring to.
Aside: Scala dev here - but I only talk about how wonderful it is with people I trust (mostly Go and Rust developers I used to work with).
Also, Scala Native means I don’t always have to worry about the JVM depending on the use case.
ScalaJS is fun too.