One 380 a day X 365 would be a drop in the bucket to the GTAA compared to what AC spends at that airport. Think of it from a business perspective. Would you take on one very small customer and piss off your main income? I don't think so.
You cannot compare the airports that upgraded to accomodate Ryanair to the YYZ. Toronto is already the largest, most expensive airport in Canada. Emirates bringing one more flight a day is not going to lead to any changes at T-1.