There's something to be said for that argument. With confederation came protectionism: Nova Scotia's ancient economic ties with New England and the other states had to be choked off in favour of Upper Canada.

Now I don't think this completely determined the region's fortunes, but you can certainly make a case for its negative impact.

European settlement proceeded westward from the east coast in both Canada and the United States, so why did cities like Boston and New York become remain centres of economic power, while Canada's Maritimes became almost irrelevant?