While Apple floundered during the 90s with their OS strategy, their API strategy in OS X has been absolutely rock solid.
It's now 2016, Carbon has come and gone as it was intended to and Cocoa is still around and is still the API you use for working with the Mac. If you're trying to do something on the Mac, there's going to be a single officially supported way to do it and that's it (if it's supported at all).
Meanwhile, there are three totally different frameworks on Windows that you can use to do the same thing, all of which are officially supported and none of which are deprecated.