Whenever I use “they” for the third-person singular, I feel feminist pride but grammatical guilt. But that grammatical guilt may become a thing of the past. Language is always changing and if it gets used enough, “they” might be here to stay. Credit to The Sociological Cinema for finding this video.
If you don’t watch the video, the main idea is that “they” in its various forms could be used for the third person singular.
I think this could work, but power and language are related. Editors would need to make “they,” or another gender-neutral pronoun, the standard for their newspapers, journals, and books for it to be legitimated. If high school teachers presented it, future generations would not see it as an innovation. For them, it would be the way English is supposed to be.