Whipper Billy Watson didn't do it. Neither did Hulk Hogan, The Sheik, Buddy Rogers, Lou Thesz, Bruno Sammartino, Ric Flair, or even Andre the Giant. In fact, very few wrestlers did it after the 1930s -- made their big-venue Toronto wrestling debuts in a main event.
It was easier to do in the 1930s because the weekly shows only began in 1929, so more wrestlers were making their debuts. And the undercards were much shorter, so a greater percentage of wrestlers on a card were in the main event.
These lists are in chronological order.
Ed Don George
George "Dazzler" Clarke
Lord Athol Layton
Lord James Blears
Antonino "Argentina" Rocca