This is hardly ground-breaking news. These cities have been on the decline since the steel crisis of the 70's. Detroit can add civil unrest as another reason.
Toronto is a city that shows signs of decline. The city proper grows at a snail's pace, the financial house is not in order, and conservatives are in power in all three levels of government (two for now, three once Hudak gets in) and this will mean zero spending on infrastructure or expansion of services. Forget that expansion of the subway Ford talks about, even if the money was there shovels don't hit the ground around here unless there were 42 studies, 72 public consultations, 16 environmental assessments, 22 protests and sit-ins from special interest groups each wanting the money to go to a pet project like more food banks, homeless shelters, safe-injection sites, tax cuts, roads and freeways, a museum of something that nobody cares about, or some grand piece of public art that everyone will hate, so you'd be looking at 50 years for one km of track. 25 if the NIMBYs can be placated without too much of a fight. Don't forget all three levels of government have to spend about 15 years arguing that the other two levels of government should bear the entire cost of the project.
Toronto suffers from white-flight unless you want to pretend that the masses fueling the explosive growth in places like Milton, Oakville, Halton Hills and Bolton is really all immigrants. The west is the net benefactor of all this. The axis of power and capital is increasingly being tilted westward, and it's not at all improbable that within 20 years there will be half a million former Torontonians in Calgary who will remind the natives at every turn that they (Calgarians) are uncultured hicks, that the food and nightlife is better in Toronto, how great the Leafs are, and how Calgary just generally sucks -- just like the legion of former Montrealers in Toronto.