Totally.
Cocoa, Objective C, OpenGL, etc, are all going to die some day and Apple will announce it a year or two in advance like they usually do with major breaking stuff. Any serious company would announce these EOL 4-5 years in advance.
With Apple the only safe strategy is to keep investing dev time to update everything to the newer stuff or let the project die because in 2-3 years max it will most likely stop working.
It's no coincidence all big Mac apps (other than Apple's own stuff) are actually cross platform projects. No wonder Apple is trying to bring people over from iOS with Catalyst.
I was going to start a macOS product this year but with the transition to SwiftUI I decided it was a really bad idea to invest in a Cocoa project.
And Jesus don't get me started on having to update the OS to get the latest Xcode version every year with their half baked macOS versions.