> But, TBH, I think Kotlin and Java
I agree wholeheartedly.
But there will be a demographic of people who know Rust and not Java, but who might want to build an app. Somewhat similar to how there is an apparent need for "HTML+JS+CSS"-devs to build native apps.
Well, this is always a tradeoff: the cost of being away from the mainstream may outweigh familiarity with a programming language at some point.
I'm not sure if the argument for "HTML+JS+CSS" is purely familiarity, there's also technical arguments like portability and future-compatibility. But I _do_ hope that the portability story will become better in the coming years beyond just this stack.
But, TBH, I think Kotlin and Java are _indeed_ fine application languages.
What Rust is already quite often used for is for libraries that work on both iOS and Android. For a public example, see the Glean SDK: https://mozilla.github.io/glean/book/index.html