I have been wondering recently if Apple are bothering to maintain the Unix side of the OS. Seems like they occasionally remove or deprecate stuff but don’t put any serious effort into maintenance.
It was arguably always halfhearted at best. Look at how behind they were on many things for years. They update things, I assume, when necessary to make the build toolchain work, and possibly to hold onto their POSIX compliance status which some us government buying contracts demand. The fact they changed the default shell to zsh instead of that decade(s)-old version of bash they used to have (avoiding a GPL license change, I think?) was a miracle.
This is just another one of those smells.