Swift is a beautiful language but you want to keep it all to yourself. We don't know that's true or not. AFAIK, Apple has not officially commented on this topic.

Actually, having spoken with Swift team in Apple (rather not mention their names in case they get in trouble) on this topic, they seemed to be happy opening it up in general and opening it up as a general purpose language. Swift could ultimately replace C++ as the language of choice for game development and more.

That said, IMHO, the language will progress a lot faster initially if it's driven by a single master than to be pulled into many directions.