Also, remember that the /usr used to mean "user", as in, if you were "bob" then your home directory was /usr/bob. That dance was done twice! Moving stuff to /u

Also, remember that the /usr used to mean "user", as in, if you were "bob" then your home directory was /usr/bob. That dance was done twice! Moving stuff to /usr/bin made sense after systems got too big for a single volume and you've got this directory on a nice, new spacious multi-megabyte disk (oooh!) In those ancient days of Unix the sysop acting as the "bin" user owned /bin and the files inside it and could overwrite them from tapes or compilation. (root would own the files in the sbin) So /usr/bin technically started out as his or her home directory when logging in as that account... at least back then. /usr/sbin only came about after /home became the colloquial location for home directories, such that you had parallel constructions for /bin and /sbin under /usr, and later, /usr/local just as you did at the root.