Many other people were thinking and writing about gender at roughly the same time as Money. He got a lot of popular attention because his experiment was glamorized across several big magazines, but academics who study the subject more thoroughly than I assert that while Money’s work was important, it was neither foundational nor necessary for the acceptance of people we now know as transgender.
It’s possible vocabulary would have been different if not for Money, but people who ought to know say that experiences probably wouldn’t have differed very much.
Even without Money, Judith Butler would still have written her seminal work, because people were thinking about the issues she wrote about with or without Money.
But of course the real point here is that Money actually experimentally demonstrated the idea of gender dysphoria, in a horrifically unethical experiment, but nonetheless.
David Reimer, growing up with no reason to believe he was not a girl, experienced such intense gender dysphoria that he refused to see Money any longer.
According to Money’s discredited theories, this should not have happened. David should have “become” a girl.
So even though Money might have (and there are conflicting claims) coined the words transgender and gender identity, what he meant by them are very different from what people mean today or even as far back as the 1980s when serious theoretical work in transgender identity first began.