The difference to me is that under iOS, you can go without these things (third party libs, Cocoapods/Carthage) and still be OK — you'll be at a relatively minor inconvenience, not ripping your hair out. Particularly with your example of Alamofire/AFNetworking, there's not a ton of functionality you're missing out on if you instead use NSURLSession, since they're both just light wrappers around it. This wasn't always true, but Apple recognized the gap in functionality and fixed it.

I have multiple personal Obj-C/Swift projects on iOS and macOS that don't use any kind of dependency management and use very few third party libraries and working on them has never been an issue or source of pain.