Red, I think I speak for a lot of us here when I say that I wish you came around more, like things used to be. That goes for you too, Bruce!
Upon thinking of your post, I am tending to agree with your premise. Teflon and copper would have no interaction with one another. However, I can see how the plasticizers(almost always pthalates) in the teflon tubing, added to make the insulation flexible, probably have an acidic, therefore corrosive effect.
Copper reacts readily with all manner of materials, and this reaction(corrosion) would definitely be detrimental in the long run. Now, I believe I finally understand the reason behind many copper cables deteriorating over time, most notably the wire used inside Legacy speakers exhibiting their notorious green degradation(copper sulfate?) despite being protected from the outside elements. The copper is being attacked from inside the insulation.
Silver coating on copper would provide a useful means of protection. Silver is one of the 8 precious metals, a main characteristic of this category being its members resistance to reacting with other compounds. So, I now see a potential long term benefit to silver coated copper. Those old engineers again get a tip of my hat. I think the cable world needs more material scientists designing products and less marketing/salespeople.
Now, I leave it to the cable producers(uuuggghhhh) to produce good sounding silver coated copper audio cables. While I admit to taking a step forward in this thread towards this material, I still maintain that the material is used mostly as a tool to sell a cable at a higher price/markup.