Comment by JKCalhoun

All new projects I was involved in over the past three years or more were in Swift. I would say it is considered in bad form to start a new project in anything other than Swift.

Further, I saw many legacy projects move from Objective-C to Swift (Podcasts comes to mind). (Some legacy Objective-C apps like iTunesU, sadly, were "sunsetted".)

Until recently, I believe there were issues with frameworks written natively in Swift so I saw a few smaller frameworks thrown together in Objective-C. I believe that, whatever the issues were, are no longer pertinent.

I can say too that there are many engineers that don't even know how to code in Objective-C. The younger engineers learned on Swift and are even hostile to writing in Objective-C (ha ha).

Of course Apple is a big company and I can't speak for the whole of engineering - only the teams/orgs I was involved with. And since I left Apple last year I can only guess at the current state. But the direction was clearly away from Objective-C.

As you can imagine, the biggest hurdle to 100% adoption is going to be bringing over legacy projects. Porting to Swift will probably always take a back seat to features, bug fixes. If the pace at Apple were more leisurely, not a suite of new OS releases every year, perhaps we could have our cake and eat it.