while gender/sex is often beside the point, number often matters. we can keep the gendered pronouns for the few cases where it's needed, and use ungendered pronouns in the general case, but that requires an unambiguous singular ungendered pronoun.
English already dropped it with 2nd person, settling on the plural (and formal) “you” as the sole pronoun and dropping the informal singular “thee”; and for 2nd person distinguishing number in the pronoun is probably more often an impediment to discussion than 3rd person (a 3rd person pronoun needs an explicit referent in the framing context anyway, so you don't lose much by not adding a reminder of number into the pronoun itself.)
Even if we could, it's still not clear what the ideal solution would be. There are cases where you need to communicate ambiguous number too. It might be nice to have pronouns that distinguish "definitely more than one" from "potentially more than one".
Your assurances don't mean much compared to usage going back to at least 1382: https://en.wikipedia.org/wiki/Singular_they
https://public.oed.com/blog/a-brief-history-of-singular-they...
Language evolves, and this means that the rules of grammar do too. The MLA already allows for pronoun usage to match that of the preferred pronoun of whomever you are writing about, and are considering allowing for the singular they in general. Some style guidelines already allow it. Others still proscribe it.
Plenty of news organizations, including the Washington Post, have set their style guidelines to use the singular they.
It's grammatically correct in plenty of places today, and the current trend is for that to increase, not decrease. You're fighting a losing battle here.
Let me rephrase that reply: Everyone is entitled to his own opinion.
Everyone takes the singular, but in that reply, I paired it with the plural their.
> she/he (not sure)
English is really strange around gender, and idiomatic styles have changed over time. It has always been a valid style in English to use "they" to refer to a single person of unknown gender [1]. This feels natural to English speakers when the subject is unknown and could be one of many potential people, as in:
When the first guest arrives at the party, give them a balloon.
Here, "them" only refers to a single person, but it's correct.
For the past hundred years or so, it was also common to use "he" to refer to an unknown hypothetical person. You see a lot of textbooks that do this. In theory, this wasn't supposed to come across as being exclusionary, but obviously it is. It's an explicitly gendered pronoun.
The feminist movement rightly drew attention to this problem, and writers experimented with a variety of approaches. Sometimes, at the beginning of a book you'll see an explicit "apology" saying something like "we use 'he' but don't mean it to only apply to males". Some simply switched to using "she" for everything. Others switch between "he" and "she" throughout, randomly or use the longer "he or she".
But, lately, it seems like the style is settling down towards simply using the already established singular they for all of these cases. To a native speaker, it feels a little weird at first, but you quickly get used to it. It's less jarring than "he" or "she" for most readers now.
It has a lot going for it:
* It has more established history than any other form.
* It doesn't force the author to pick an arbitrary meaningless gender.
* It's shorter than the awkward "he or she" (which also still forces you to decide which gender to put first).
* It doesn't exclude people who prefer neither "he" nor "she" as their pronoun.
So, if you're trying to figure out what pronoun to use when you don't know a specific one that is correct, default to "they".
[1]: https://en.wikipedia.org/wiki/Singular_they