It's certainly a thought-provoking question.
Canada still has two official languages, the two languages in which its national conversation is conducted. Unless I'm mistaken, people have to speak one official language or the other to immigrate to Canada, so it is up to them to choose which one. That's how it works under the current system. Obviously, some of your observations would come into play if there were talk of changing the official languages regime.
Francophone immigration outside Quebec is without question crucial to the survival of those French-speaking communities. Even though the number of French speakers is on the rise, as the numbers show, the francophone share of the population continues to decline.