It is a fools errand to think Kotlin/Native would ever overtake Java.

Only on Android it might have a future, if Fuchsia never becomes a thing.

On what concerns the JVM, Kotlin hype will be over in a couple of years, and it will get as much use as Scala, Clojure, Beanshell, Groovy enjoy nowadays.

Guest languages never get to own a platform, and with time all platform languages end up getting enough features that the large majority of developers never bother with extra tooling, debugging layer and idiomatic wrapper libraries of the guest languages.

And we know that because?

>Guest languages never get to own a platform

That depends on the platform, who is running it, and how. You couldn't have a worse steering than Oracle.

And most "guest languages" are smaller affairs, they don't have companies the size of Google chosing them for Android app development (a huge niche in itself). Or have first class support from the most popular IDE of the host environment.

Plus, anything is anecdotal, as we have so few cases of major parent/host language rivalries, and even fewer cases with similar dynamics, that there's no real prediction.

Scala was too complex for most Jave-ers, too slow to compile, didn't have a Google pushing it to its platform devs but an insignificant company, etc. Clojure was a Lisp (= doomed), Beanshell and Groovy where from small, insignificant origins, and not pushed by anyone really mainstream the size of Google/FB/etc.

Kotlin doesn't have any of those issues.

Heck, even Elixir does quite well I hear.

UNIX and C, Web and JavaScript, Windows and .NET/C++, macOS and Objective-C/Swift, Android and J̶a̶v̶a̶/Kotlin/C++....

Google only cares to push Kotlin on Android, and it only matters because Google visibly doesn't want to move Java beyond the Java 8 subset that Android currently supports, so the choice is between an handicapped Java support or Kotlin.

Until there is a JVM written in Kotlin, and Kotlin gets first class support in all Java IDEs instead being a tool to sell InteliJ licenses, it is just yet another language that happens to target the JVM.

This ignoring that Kotlin already has a couple of impedance mismatches with the JVM, sequences vs streams, lambdas vs SAM, co-routines vs fibers, inline classes vs data classes.

Elixir is doing well because many developers seem wary to learn Prolog/Erlang syntax.

They do up to the point where they differ philosophically. Java is never going to turn in to a Clojure, nor is it going to adopt the type of dynamic scripting features Groovy offers.

Kotlin and Scala are more at risk in that way.