The population in Canada is almost 35 million souls. Reference:
https://www.google.com/search?q=population+in+canada
Therefore, a third* of the population represents about 11.3 million souls. Of course, that entire "third" are not all Leafs fans. You have Montreal, Vancouver, Edmonton, Calgary, Winnipeg, and Ottawa as well. So how die-hard Leafs fans are there of that 11.3 million, really?
How many Kings fans are there, not only in Los Angeles, but also throughout the league?
You begin to get my drift. No, Toronto is not the most important team in the league. Not by a long shot.
*There is no empirical data for this contention.
This simply is not true. There are 300 million souls in the United States, almost ten times as many as Canada. Of course football, by its sheer numbers, is far bigger than ice hockey in Canada.
By the way, the NFL has gotten along just fine without a team in the second largest city on the continent.