Relationship with MPS

Given Kotlin's focus on allowing domain specific languages a la Kara, I'm wondering if the Kotlin and MPS teams will ... well ... team up, at any point? It seems odd that JetBrains is developing this very powerful semi-graphical language platform MPS, and a Java compatible language with DSL-like features, but there's no collaboration or compatibility between them.

For example, could Kotlin be implemented as an meta-programming system language, or is that not possible because some Kotlin concepts cannot be expressed as Java source code? Could MPS Base Language be extended to allow Kotlin to be implemented in terms of it, allowing arbitrary mixing/matching of non-textual languages with Kotlin source?

Any language can be implemented in MPS, Kotlin is no exception.

Yes, I know that. I suppose the obvious question then is - why does Kotlin not work that way? Is MPS not mature enough for that yet?

For the same reason why MPS did not replace IntelliJ IDEA: many people prefer textual languages to semi-graphical ones.