> I don't have much faith in broad adoption if the term can't seem to penetrate usage in writing outside of contexts where people are actively discussing the term itself.

The usage doesn't need to spread beyond discussions of the term itself, because it was already being used long before these discussions. That's why I linked to the articles about Shakespeare's and Austen's usage, they are data. I find it a bit of a stretch to interpret that as me saying "you obviously haven't read Shakespeare and Austen" (in any case, I've never read Austen myself and definitely can't remember what pronouns Shakespeare used from what little we read in school; I leave it to the historical linguists to dig out the usage examples).

Back to the matter at hand, if you want something definitely contemporary, of the five first tweets at https://twitter.com/search?q=they I see two which could have been replaced with "he" ("if someone wants to follow you {he,they}'ll follow", "Never miss an opportunity to tell someone how much {he,they} mean to you.").