I don't think it was a conscious decision to not support Gradle, etc, it's just that sbt had a few highly motivated maintainers. This meant that sbt became the

I don't think it was a conscious decision to not support Gradle, etc, it's just that sbt had a few highly motivated maintainers. This meant that sbt became the easiest tool to use when starting a Scala project. sbt's incremental compilation was also very important for a language with long compile times and still-developing IDE support. It would be great if Scala had great Gradle support. Nowadays some large Scala users maintain Gradle support for Scala to a good level.