Maybe you are just not in the target market? I just checked FlutterShark and I have 14 apps installed with flutter in it.

Flutter is starting to become the default framework to build apps in in Asia at least.

And I disagree about the LLM, Flutter provides strong standardisation and strong typing which make it an ideal target for LLM.

As for Kotlin Multiplatform, maybe it will take off similarly as Flutter but that hasn't happened yet.