Given the desire to now remove the natural gas from the arctic field in mass via another wholesale pipeline, because a more rationed approach to slow the demise of a local resource isn't on the table for future usefulness. And nobody underwrites long term thinking, because it just isn't profitable. 

What energy source will be available should someone wish to extract thick 'tar sands' quality crude to transport it as thin pipeline grade syrup? As that also is corrosive, extra costs= less profit. You can say 'Alberta surface tar sands mining' then consider it is heavily subsidized, with extra costs to other life on earth.

{The insane driver of long term investment in short term exploitation of limited resources. Get it now, sell it cheap; race to the bottom.}

There is no savings having a reservoir of heavy crude near the Arctic Ocean. Nor is there any - should the same poor quality be near ice-free Tidewater - elsewhere in AK waters.