Re: What's Swift even supposed to do?
That's basically it: Apple wanted some kind of intermediary language for developers. In a sense it's competing with Dart and Typescript and the other also rans. Rust has at least carved itself a niche in the systems world. For the rest, it's increasingly looking like be able to compile to Web Assembly is all that matters.
Apple hasn't helped by being lukewarm about the project: slow to open source it and not giving it the kind of resources Google likes to throw at projects. That said, it's probably got a dedicated group of happy users.