What prompted Apple's transition to Swift?

John Siracusa has been beating this drum for a while now. Basically, good platform stewardship requires advancing the state of the art in development at best, or at least keeping pace. The worry was that apple had ceased caring about the future of their platform from a developer standpoint. http://arstechnica.com/staff/2005/09/1372/

From a business metric point of view: it is probably one of the best things they can do to reduce the global number of app crashes, which I would think is a driving factor in customer satisfaction.