Not Even Apple Knows Swift Yet
That's not to deny your own personal experience if you've been experimenting and building some things in Swift - certainly people know how to write Swift - but what they know is limited by a lack of experience, a lack of real-world testing. As a whole, Swift is marked by a sense of incompleteness. The reason, Napier suggests, is that Swift didn't go through the motions (internally) that many releases would; essentially, current users are the beta testers for something that ordinarily would have been beta tested already:
Swift has come naked into the world. Half-baked. Some parts ill-considered and changing dramatically before our eyes. Most of its libraries are still in ObjC, C, and C++. It’s just the beginning and you’re all here. You’re those early adopters, usually that tiny, almost hand-picked group. But there are thousands of you this time, here in the priomordial era.
Napier's point is not to criticize, though; he sees this as an opportunity to truly be on the cutting edge of a new technology which, given that it is Apple's new preferred language, is fairly major. By getting involved with Swift now, developers can truly say they've been there from the beginning, and can have an impact on what direction the language does or doesn't take. It's definitely an interesting situation, which Napier makes clear enough:
So there you go. You’re here at the beginning. There is no priesthood. There are no old folks sitting on rocking chairs cussing your new-fangled dot-syntax. You are the old folks. You remember before immutable arrays.