There isn't any good evidence of how many times Joplin played at the Midway. Most of the evidence is from interviews decades later. Similarly, we actually don't know what kind of music his band was playing. It could have been early rags, but if they were, they didn't make waves the way lots of other art and ideas that debuted at the fair did. Certainly, ragtime was not associated with the Fair in subsequent memory.
In next week's post I am actually going to discuss the way the fair is considered the beginning of certain ideas (in urban planning specificalyl) that already existed—but maybe need a big white puffy outfit to truly debut.
Since Maple Leaf Rag wasn't published until 1895 maybe they felt it wasn't ragtime until then? Although my understanding, which I thought was pretty conventionally agreed on, has always been that Joplin appearing at the fair was what helped make ragtime a national pop phenomenon of his time. But maybe I should reconsider that because ragtime didn't become big until after 96-97.