In light of that, then another (perhaps more charitable) way to look at it is that the maintainers are keen to clean up stuff that they perceive as old cruft, and perhaps don't realise quite how ingrained these particular pieces of "cruft" are into the ecosystem.
(On the other hand: the same POSIX link specifies the removal of cpio and, uh, tar. I'm not sure I see that last one flying.)
[1] https://pubs.opengroup.org/onlinepubs/9699919799/xrat/V4_xcu...