Respectfully disagree. Swift is still largely Apple-centric. That means its primary popularity will be for writing macOS and iOS apps.
Yes, I am aware of attempts to make Swift useful outside of Apple. Swift will be competing against many, many other languages (eg, Ceylon, Dart, Elixir, Go, Julia, Kotlin, Rust, Scala). All of them have vocal fans, growing ecosystems, and significant mindshare. Swift is not in the least bit unique nor special. It is not at all compelling as a programming language.
I don’t believe Rust will ever become mainstream. It has some interesting concepts, but it doesn’t have enough to overthrow C/C++.