at the time, lots and lots of scripts would place things in /tmp/scriptname-$PID so you could race them, since you can know where it will write things, other sc

at the time, lots and lots of scripts would place things in /tmp/scriptname-$PID so you could race them, since you can know where it will write things, other scripts would use PID for random which is equally bad, especially for things that run from rc scripts at startup, so I would say "nothing was gained" is a bit of a stretch. After a while, mktemp got more usage (which is good) and $RANDOM became available for scripts and so forth, but the situation was quite bad 20+ years ago as far as vendor installation scripts went. Perhaps exactly noone was saved on OpenBSD because few installed linux-compat Netscape 1.1N for i386 with a bad installation script while having adversarial users logged in, but there is no reason to be equally bad as the then-more-popular OSes who did see /tmp races being won by users.