macOS also does a more strict but tidier hierarchy, grouped into "domains" … /System/* is "stuff from Apple" (including /System/Library, etc.), / is for "stuff on the local machine" (/Applications, /Library, etc.), and then each user can have their own hierarchy in their user directory (~/Applications, ~/Library, etc.).

Of course, the "stuff from BSD" winds up in /bin and /usr/bin anyway, so it's still a mess.

https://developer.apple.com/library/archive/documentation/Fi...