As an Android dev, I disregarded any company hiring that was not transitioning to Kotlin. It was a major red flag if the project was relatively new. My personal project on spring boot is completely powered by Kotlin and I fully expect KotlinJS to be ready for production in a year or so for full stack development.
Writing in Kotlin really is a nicer experience and with near full access to all the legacy java libraries I would never want to switch back even with the small improvements java has made to be more like Kotlin. I highly suspect as the number of java devs that are exposed to Kotlin increases the number of devs happy to write in Java over Kotlin (or Scala) will decrease. Android going Kotlin first was in part justified by giving the decision makers a short period of a week or two to get adjusted away from java and see how they felt about the language in comparison
I agree with everything you say, but that transition will take time. I think Kotlin is a great language, and combines a lot of the best strengths of others while not giving up that JVM tooling goodness. However, I think you still need to have good Java chops to work with Kotlin, at least to deal with those dependencies. In fact, its almost exactly the situation that TypeScript has: yes, its a good language, but you can't really use it well unless you know JavaScript (and in particular, ES6) really well. Edit: sorry, I'm really talking more generally than Android. You're probably right about hiring for Kotlin for Android instead of Java. But Kotlin is targeted at everything, and for that I think it's probably good to wait a bit.
Writing in Kotlin really is a nicer experience and with near full access to all the legacy java libraries I would never want to switch back even with the small improvements java has made to be more like Kotlin. I highly suspect as the number of java devs that are exposed to Kotlin increases the number of devs happy to write in Java over Kotlin (or Scala) will decrease. Android going Kotlin first was in part justified by giving the decision makers a short period of a week or two to get adjusted away from java and see how they felt about the language in comparison