Swift is a very powerful and robust language. I would expect that they keep going further down the stack with it but the problem will always be, "is it worth i

Swift is a very powerful and robust language. I would expect that they keep going further down the stack with it but the problem will always be, "is it worth investing in a language refactoring on an existing codebase?". I presume all but the lowest level (or server-side) new code is in Swift at Apple nowadays.