Earlier quoted context omitted.
The amount of ObjC sessions at last WWDC 2015 and the upcoming WWDC 2016 send another message.
ObjC will be around much longer than 3 years. It can't be deprecated until most of OS X is rewritten. Remember how long it took them to get rid of the Carbon Finder?
Apple even mentions Swift as a C and Objective-C replacement on their documentation.
Of course, it doesn't make business sense to stop the engines and rewrite all the stuff.