I enjoyed Scala. I don't think they're what killed Scala. I think what speed down Scala adoption was that it was too related to Java and on top of that Java was adopting much of the functional paradigm taking a bite out of scala's dinner.

Scala was adopting functional enthusiasts and the JVM again was to related to Java for their tastes. And if not, then they could just go to Closure anyways.

But in my case it was Rust. With Rust I could also get into systems programming if I wanted to and didn't have to worry about the JVM.

The JVM is really the only reason I have yet adopted Jenkins as well.