It’s a good question though. If you look at what Einstein used, it wasn’t entirely revolutionary in its parts. Lorentz for example, was crucial – and in fact I can’t see any reason Lorentz COULDN’T have done it himself, except that he didn’t.
I think what Einstein *did* have that that most of his contemporaries *didn’t* have, is a sense for how to utilize mass media.
He was THE 20th century SUPERSTAR of Science. Newspapers would ask him all SORTS of questions including things he knew nothing particularly special about, just to get a quote and Einstein ate it up, adoring the fame and publicity.
This is what, I think, made Einstein such a stand-out figure: He was good at doing that.