Modern BSDs, macOS, and Solaris certainly have Perl and Python. (iOS and Android don't, but they don't have awk either.) What other Unixes are you thinking of? AIX, HP/UX, IRIX, UnixWare, etc. should be considered retrocomputing at this point and not relevant to modern compatibility discussions.
Linux distros based on busybox, as mentioned elsewhere in this thread, are a more compelling reason for considering awk than considerations involving other Unixes.