That's totally fair, but I think the point that "every 'new' macOS app from Apple ... has been written in either SwiftUI or Catalyst" isn't really surprising. New features are probably going to rely more on newer technologies – especially in places like Shortcuts & System Settings, where the legacy approaches had non-trivial security implications. And, at least so far, we've only seen Catalyst apps from Apple when either:
(A) an app was being ported from iOS because it didn't already have a native Mac counterpart (e.g., TV, News, Podcasts), or
(B) the Mac version was significantly behind its iOS counterpart from a feature perspective (e.g., Messages).
I had written a diatribe earlier about how I don't see this as equivalent to the Cocoa/Carbon situation, but deleted it because I'm being long-winded enough already. It boiled down to the fact that Carbon existed specifically to help port apps from a legacy OS to what Apple was loudly declaring to be the future: OS X. Carbon was a way for apps to get off the sinking ship that was the "classic" MacOS. I mean, they had a funeral for it! https://i.imgur.com/KjFh63u.jpg
20 years from now, will Apple's macOS apps contain more Swift+SwiftUI than Objective-C+AppKit, probably! But I'm not worried about AppKit being a "dead end" until they rewrite Mail, Keynote, and Xcode – because they have significantly more invested in those apps than I have in my AppKit apps.
(For the record, I love SwiftUI, and use it whenever I can! I just have no expectations that AppKit is going away any time soon.)