You’re comparing apples to oranges. Despite its low overall population density, Canada is a much more urbanized country than a lot of outsiders may realize. Almost two-thirds of the country’s population lives in its ten largest metro areas.
I’d say it is even more urbanized than that if you begin by defining the GTA generously as one urban area.
Toronto and Montreal are very big—Toronto is bigger than Chicago even without any of its suburbs, which add loads of people.
That said, a socialized medical system that manages to be decentralized enough and flexible enough to exercise discretion and getting testing on line quickly isn’t just a result of urbanization.
The containment thus far is remarkably effective.
It also helps that the urban areas are very isolated from each other for the most part. Nothing like California or the North-East.
Thus far I think only a handful of cases of in-country transmission, and only 15 or so people out of 140 or so hospitalized.