When NeXT still existed and the black hardware was a thing, Steve Jobs made the announcement that OPENSTEP would be created and that the object model, not the operating system and not the hardware, was the important thing.
This is a concept that Apple has forgotten. With it’s push towards Apple Silicon and a walled-garden, Apple has committed itself to the same pitfall that NeXT fell into. NeXT lacked the infrastructure to handle OPENSTEP running on multiple kinds of hardware, but the object model on different OSes was successful… this is evident in OPENSTEP1.1 for Solaris and OPENSTEP for NT.
GNUstep attempts to reach the same goal, but provides the APIs that are available with Cocoa. The object model IS the important thing and this is why GNUstep is so important. It breaks the walled garden and makes it possible for users to run their apps and tools on other operating systems. GNUstep HASN’T forgotten and we believe this is a core concept that Apple has left behind.