@yole has just explained the motivation of JetBrains and technical constraints of the current LSP version. JetBrains invested a lot in Kotlin and gives it away for free. You can even get a world class IDE for free with excellent Kotlin support. There is nothing special with Kotlin or the license that would hinder anyone to build another IDE or plug-in. But it is a bit strange to accuse JetBrains of not working for the competition.
If you miss LSP support for Kotlin than why don’t you help to improve it?