I think Apple has been clear that much of the underlying mechanics of Swift remain tightly coupled with the ObjC runtime, which makes sense if you think that Sw

I think Apple has been clear that much of the underlying mechanics of Swift remain tightly coupled with the ObjC runtime, which makes sense if you think that Swift code must interoperate with all the existing Cocoa and Cocoa Touch frameworks and third-party code written in Objective-C (thus also allowing Apple to hedge its bet in case Swift tanks with developers). What's _really_ going to be interesting going forward is whether Apple introduces new features in the runtime that are only available to Swift code, or whether it starts making change to the runtime that favour Swift over Objective-C—and that's probably going to tell us when the latter is to be considered a legacy language.