Wow, I didn't expect such differences compared to Scala. These graphs need a study on their own.
This could be a factor:
> On 12 May 2011, Odersky and collaborators launched Typesafe Inc. (later renamed Lightbend Inc.), a company to provide commercial support, training, and services for Scala. [0]
[0] https://en.wikipedia.org/wiki/Scala_(programming_language)