Kotlin never fixed anything on this area, beacause it is a guest language for the JVM, and the whole Android tooling depends on Java and JVM, ART only runs on the devices.
So to be fully Java/JVM free with Kotlin-first, Google and JetBrains would need to re-write the Android world to run on ART or Kotlin/Native, including anything that might come from Maven central.
Copyright in a private, internal API seems reasonable in principle.
RIP kotlin-first on android?