Swift was a play by Apple to make application developers (and I suppose their own internal developers) more productive. Swift absolutely became successful because it had a strong reason for developers to learn it. That said, it probably also made Apple more successful in some way as well as you cannot undercut the value of productivity.
Looking at the application landscape (and quality) in the early years of Mac OS X with Objective-C and later on with Swift, I‘m not so sure about that. Even worse when you look at Cocoa vs SwiftUI.
