De Havilland is another Canadian aircraft manufacturer, and is expanding massively right now. But I suppose they serve a different, simpler market than Bombardier.
To your point - Even as domestic "competition", the market is still separated by aircraft type.
And honestly, their history is a good example of why countries act in this way. When they were sold to Boeing, it seemed to be a way for Boeing to "grease the wheels" in order to land a big Air Canada contract. When Airbus got the contract instead, Boeing immediately put De Havilland up for sale and let the company languish until it was purchased by Ontario/Bombardier. Corporate histories can be interesting!