Whoever wrote that article doesn't understand Swift well, or Apple for that matter:
Swift is designed to support a world built bottom up in Objective-C. It's meant to play well with the bazillion lines of existing Objective-C, not supplant it.
This is totally wrong. Apple could not be more clear that Swift is built to supplant Objective-C. It will take a while to re-write the frameworks but they are encouraging everyone now to write new stuff in Swift, and as rapidly as possible making the bridge over to the Objective-C frameworks as Swift friendly as possible.
I think Apple will not open Swift at the moment because they want to have a small core group directing where the language goes, at least at first... and then it will open up more from there. But that also supports the notion that swift is not an auxiliary language, but the primary path going forward.