With that said, kernel maintainers have recently indicated that some unused subsystems are likely to be removed soon, as AI is now finding (real) security vulnerabilities in them that nobody is willing to fix.
Looking through Apple’s financial statements, they theoretically could support these old systems. I’m not saying a cut doesn’t make sense, but just that economics-wise they could keep one guy for it
IIRC, that could exist for MacOS in the form of Darwin.
And that increasingly gets difficult to do. i386 support went down the drain in the kernel in 2012, i486 is probably going down the drain as well this year [1] and soon-ish another bunch of really really old stuff will go as well because it isn't maintained [2] - good luck finding someone still running IPX networks or ISDN hardware.
[1] https://www.theregister.com/2026/04/06/patch_to_end_i486_sup...
These arguments fall apart when you remember that Apple has several trillion dollars at hand. It's not some shoestring startup.