As someone who grew up, and still continues to be a part of the Toronto theatre scene, I want to say that more often than not, Toronto could sustain a 6-12 month production. There are some shows that can fair better or worse depending upon the show. Dear Evan Hansen just seems to be one that didn't catch on. Thinking back, the family shows, and fun splashy shows seem to do better. (Joseph, Mamma Mia, Dirty Dancing, Kinky Boots, Lion King, Beauty and the Beast). It's hard to mention Come From Away, because this seems to be a juggernaut, especially given the content.
Something that comes of interest for those non-Toronto people, is that in the downtown core, the six commercial theatres that can accommodate for Broadway tours/productions 4 are owned by the Mirvish Family (Princess of Wales, Royal Alexandra, Mirvish, and the smaller CAA Theatre), the main presenters of tours. One theatre is owned by the province of Ontario (Elgin Theatre), and don't actively look for tours, they wait until shows book them. The last theatre is owned by an agency of the city government (Sony Centre for the Performing Arts) Since being built in 1960, and opening with the World Premier of Camelot, this was THE place to see Broadway shows until the late 1980's when things started to turn around. They haven't really presented Broadway tours in about <10 years. They are actually bringing the Non-Eq tour of Spongebob in December 2019. The theatre that Drabinsky help build in the northern part of the city, about 20 mins from downtown on the subway, (Toronto Centre for the Arts) has recently been renovated, and the largest theatre that saw pre-Broadway Ragtime, Fosse, Show Boat, and the Canadian Sunset BLVD has been divided into 2 smaller theatres.
So, if Mirvish doesn't bring a show, you are SOL unless you are willing to travel to Buffalo or Detroit.