Can "they" go mainstream as a gender-neutral pronoun?

Can using "they" as a gender-neutral singular pronoun catch on in the mainstream?
As Miss and Mrs. made room for Ms., can "they" make the spectrum between he and she more "thinkable"? (Fabiola Carletti/CBC)

In queer and progressive circles, people who inhabit the space between "he" and "she" have been called "zhe", "hir" and other gender neutral pronouns. But as educator Davey Shlasko can attest, those terms haven't caught on in the mainstream. 

Today, Shlasko joins guest host Rachel Giese to argue that "they" -- as a singular pronoun -- can bridge the gap, despite the protests of grammar sticklers. Shlasko argues that "they" is not only a respectful way to refer to people whose gender identities are outside the male-female binary but also a familiar enough term to see more widespread usage. 

Click here or on the listen button above to hear the full segment (0:21:58).