And let's be real here, MAJORITY of Toronto sports fans are fairweather fans who are bandwagoners.
Among those who are Leafs fans, a huge chunk are oblivious to hockey or the nitty gritty of the sport in general, and just watch because it's the thing to do here
When I think of Toronto sports fans I think of morons who boo Ottawa and Montreal, but when it's either of those teams in the playoffs, they go to Boston Pizza to cheer them on "because they're Canadian"
Most fans in Toronto are, I think, regionalists. They'll cheer hardest for the Leafs, their favorite players are the ones from Toronto, and the next levy below that is being a fan of Canadian hockey players (and Team Canada / WJC). The allegiance isn't to the franchise, so if another team set up shop here and stacked itself with local players, the switch would indeed be on.