It's in Apple's best interest to continue supporting both. Why? Let's just remove the POV of app developers and simply look inside Apple. The article mentioned

It's in Apple's best interest to continue supporting both. Why? Let's just remove the POV of app developers and simply look inside Apple. The article mentioned a very important point. Apple itself has not adopted Swift as fast as the developer community. This is because (I don't know this for a fact, but am quite sure), a large portion of hw/sw engineers know how to write C, C++, and Obj-C. They don't just know how to write it, I bet a lot of them are damn good at it and if not, top in the industry. Why convert? As many mentioned in the comments, it would be a huge overhaul and what about Apple's internal engineers? Would they put themselves out of a job?...Not likely. Maybe in 20 years (if there still is an Apple...), there will mostly be Swift engineers. I just don't see them shooting themselves in the foot by removing obj-c in the near future (as in 5-10 yrs).