Comment by KlayLay
People still write applications in Objective-C (e.g., see Transmission [1]), and the language is still maintained to support the latest OS. If anything, Apple being the largest sponsor of Objective-C would suggest that you get greater vendor lock-in out of it than Swift, since you can at least use the latter outside of Apple platforms (e.g., on a server).
> Apple being the largest sponsor of Objective-C would suggest that you get greater vendor lock-in out of it than Swift
Fun fact, you can use Objective-C on non-Apple platforms [1] and with Cocoa APIs courtesy of the GNUstep project [2].
[1] https://github.com/gnustep/libobjc2
[2] https://www.gnustep.org/