Alberta and Saskatchewan have a continuous supply and the pipeline would have given Irving cheaper oil than tankering it through the oceans.  In Alberta and Northern Saskatchewan as well, no fracking is required, which could damage underground water sources, because the Oil Sands have the product naturally there.   Buying oil from out of country takes finances from the country.  Buying products within the country keeps the money here.   Your premise would mean that Saskatchewan should buy wheat for bread from North Dakota because it is a dollar per tonne cheaper.  Money is gone.  GS, unless you are a globalist which has merit, then you make no sense.