"Man" was originally a gender-neutral Old English word for human beings (the gendered prefix for males being "wer", as appears in e.g. werewolf.) So why not just expand on that: demand that "man", "sir", "he", "him", "Mr"—and common nouns like "mailman", "fireman", "steward", "host", "master"—be used when referring to both men and women, and thus retroactively de-gender all previously written implicit-male-subject texts for future generations? Instead, we got "he/she", "they", "mail carrier" and "fireperson", which seems like a terrible thing to do to a previously-concise language.