There is a bit of conflation going on here. The WCS:WTI discount is shown here, and it's not 50%:
http://economicdashboard.albertacanada.com/EnergyPrice
It is significant and would be alleviated by pipelines, and the price again is presented in USD, so the lines would move a fair amount when presented in CAD.
The bigger spread is when we compare the price we get vs. WTI and then the discount between WTI and Brent (the world price). We would approach the Brent price if we had a pipeline to tidewater because we would no longer be hostage to the US policy that prevents exporting oil out of North America.
So, Albertan gasoline buyers face 2 big discounts: WCS -> WTI and WTI -> Brent, at the same time that the spread has gone down (making WCS relatively more expensive) and the CAD has gone down (making WCS more expensive because WCS is priced in USD).
It's not as simple as cross-plotting the pump price and the WTI price.
