I think the truth is likely somewhere in between.  There are applications where the aluminum substitutions could make sense - but there are lots of applications where copper is really the only choice.  The bigger the price difference the more that this will happen.   

At the bottom of the article of dsikorsk link there was this link about Lundin Mining. I totally agree with the comment at the end of the article.

Lundin Mining ready to bet on Argentina as Chile risk grows - MINING.COM

Still, he doesn’t want prices to get too high given the demands that could generate. “If the price is like this or a bit lower it’s very good for the industry to give stability and the fire-power to put new projects into production.”

To me if the price is too high then too many mines become feasible...

Anyways, I enjoyed the articles... keeping on learning.