Meh, I'm not sure it's actually hurting Kotlin's growth. IntelliJ has, from what I can tell, very close to 100% usage in the JVM world. I genuinely do not know anyone who does Java outside of IntelliJ anymore. [1]
I held out longer than most people and tried to use NeoVim for Java dev, but even I bit the bullet and use IntelliJ. Since Kotlin more or less markets itself as "Java but better", I think that it's unlikely that it's going to drastically take away from their userbase by not providing first-class support for other editors.
[1] Clojure being the only exception I can think of, and even there a lot of people still prefer Cursive.
I held out longer than most people and tried to use NeoVim for Java dev, but even I bit the bullet and use IntelliJ. Since Kotlin more or less markets itself as "Java but better", I think that it's unlikely that it's going to drastically take away from their userbase by not providing first-class support for other editors.
[1] Clojure being the only exception I can think of, and even there a lot of people still prefer Cursive.