Suprisingly, POSIX has recently adopted the find -print0 | xargs -0 idiom, so the gears do turn, but very slowly.

The latest standards for POSIX.2 utilities are here:

https://pubs.opengroup.org/onlinepubs/9799919799/utilities/

I do agree with you that UNIX userland would be miles ahead of where we are now if the POSIX.2 standard could be cajoled out of the '80s.