Just because Go, Haskell, C and LuaJIT all target x86 assembly does not mean a Linux kernel update won't break a properly-written program in one of those languages but not the others. They share the same compilation target, not the same semantics and idioms. So from the point of view of the platform there is no difference between kotlin and java.
Because the good thing about kotlin is that it is transparent, it generates bytecode as java does. > then it also breaks the same app written in java. If all Jetbrains employees were abducted by aliens tomorrow, Google will now still have committed to first-class support of Kotlin through the next couple of major versions of Android. Regardless of how the work involved in supporting Kotlin on Android is split, this represents a guarantee that did not exist before. The headline here is "Google officially supports Kotlin on Android," and that is what has HN so excited.
Jetbrains isn't doing anything differently with Kotlin from what they've been doing for the past 7 years. Google is only going to collaborate with JetBrains to help with the Android support.