Kotlin could he better, but doesn't go all the way. Without HKTs and implicit injection, Java is going to eat its lunch. Java already has records, type inference, parametric null safety with Optional, Loom provides coroutines, vavr and streaming apis have given us theabilitytodo FP... what's left as a unique feature?
Kotlin will survive because it was picked for Android to avoid copyright issues. But the difference between the two languages is vanishing small.