@davefischer
Strictly speaking that's a conflation of two distinct strands of history that were a decade and a half apart.
AT&T #Unix System 5 Release 3 had the system of subdirectories and scriptlets, developed because /etc/rc had exploded into a mess when people came to realize that sysops installed third party softwares. This was superseded by something else, the SAF, in S5R4 in 1988. Unices with AT&T heritage such as #Illumos and #Tribblix have that still today, all these decades later.
Whereas what people erroneously call "System V init" was an init+rc system developed independently, for a different operating system with a separate lineage, cloning the design of the old AT&T Unix S5R3 system of roughly a decade before, by Miguel van Smoorenburg in the early to middle 1990s. *That* is the strand of history that went from Minix on to Linux, and was in some flavours succeeded by Upstart and then by systemd.
#HistoryOfComputing #retrocomputing #Upstart #ServiceAccessFacility