Go has to contend with Swift. Rust does not.
(Also, there are concerns about Swift's usefulness on non-apple platforms if the libs aren't completely open source.)
During the WWDC 2015 opening keynote, Federighi explicitly stated that Swift's a "systems programming language" and they even say it in the documentation:
> It is the first industrial-quality systems programming language that is as expressive and enjoyable as a scripting language.
https://developer.apple.com/library/ios/documentation/Swift/...
Swift calls itself a systems language. Rust/C++ call themselves systems languages. The two sets use those words to mean different things.
A: Garbage collected vs. not garbage collected. B: Generics vs. no generics. C: Algebraic datatypes vs. no algebraic data types.
Even with these three dimensions, it's easy to separate major languages
Rust: A-B+C+, Swift: A+B+C+, Go A+B-C-, Java: A+B+C-, C++: A-B+C- (discounting union types)
tl;dr: Swift is not in the same space as Rust.