I would argue that Scala drove Kotlin. And over the last 10 years at least, it's been Kotlin driving Java.
What I saw happen was Kotlin taking over the mantle of "better java" from Scala, and aiming for an 80/20 type language compared to Scala. And for the most part, it's those 80% that are finding their way into Java.
Many of Kotlin's profound improvements will never find their way into Java because it's 25 years too late to do so. Java improves where it still can, which is the right thing to do. Sometimes Java even manages to improve on Kotlin because now it can learn from Kotlin and other languages. Nevertheless, it's impossible for Java to catch up to Kotlin, which was designed 15 years later with the explicit goal of fixing as many of Java's design mistakes as feasible for a JVM language.
What I saw happen was Kotlin taking over the mantle of "better java" from Scala, and aiming for an 80/20 type language compared to Scala. And for the most part, it's those 80% that are finding their way into Java.