<Snipped quote by Legend>
Actually, Bodine wrote her paper back in 1975 before the debate was actually becoming a debate, for the purposes of explaining what was happening. It was already accepted that prescriptive grammarians attacked singular "they", and therefore "he" became accepted. Her article is actually considering other things, but her input and quotations are useful to me nevertheless, because it shows that scholars don't need to debate that point. They have it in history.
EDIT: I don't even consider that a good argument. The fact that nobody made an attempt to write an article about the use of "he" in the eleventh century could just as easily imply that they didn't because there was no usage to write about. All it is is a fact, with no specific connotations either way.
I read that.
When there are two options, and we know for sure that they did have a word to refer to singular genderless pronouns, once one is dated to the first usage, there's no choice but for the other to exist before it. It's also similar to the IVT in Calculus, ie. an airtight argument.