Funny how experience differs. I think almost all Java teams I know use Kotlin now in some capacity, mostly for new code but sometimes for all code. Not to mention Android is a very large share of applications and Kotlin is the default choice there.
How's that relevant to people moving away from Scala?
No Java teams at my company have moved to Kotlin. There’s a is a shift of Scala -> Java, I think many people are scared of adopting a guest language again and modern Java with records, switch expressions, and sealed types isn’t bad enough to warrant the risk.