[nfriedly]

I think part of it is that there are a lot more old Android and iOS apps out there that still use Java/Objective-C. These apps are probably worth maintaining and updating, but not necessarily worth rewriting. (And, you'd still need to know the old language in order to do a decent rewrite.)

For iOS where I work, we use primarily Objective-C, with only a tiny bit of Swift. We actually have more Rust code than we do Swift. (The Rust code is for our cross-platform logic that's shared between Android and iOS.)

I think the Android side is all Java with no Kotlin at all.