The presence of students from other countries and cultures enormously enriches the learning environment for everybody, irrespective of who you are. That's true for students from Quebec, from other parts of Canada and for other international students. That alone would seem sufficient grounds for increasing their numbers. It's easier to establish contact with someone in Central Africa who is an alumnus than with someone who isn't. That's not a very sophisticated idea.
People frequently underestimate how much effort it takes to sustain something.
None of us are here forever. Sustaining them over time takes an enormous institutional effort, but that's the price that must be paid to sustain yourself as an international institution. It's always been part of our history. To focus on being a locally salient institution wouldn't be very sensible. There are plenty of universities in Quebec.