Interesting story. Once you read the url you posted several things begin to become more clear in the case you reference.Nowhere is there a suggestion or proof or even the allegation that PRS was using Gibson's name nor was PRS marketing their product as a clone (or copy) of the Gibson...
in fact... PRS had their own trademarked name for their product... SingleCut (a R trademark of theirs)...
nor did PRS claim that their product was a copycat of the Gibson.
also note that Gibson said in court that consumers would not be confused "at the point of purchase" btwn the two different products.
The case you reference above is entirely different than someone making explicit copies of a competitor's product and advertising those copies as derivative of a moreso famous brandname... if that were the case (and it was not from PRS press release) the court would have likely have reached a very different conclusion.
What the courts will look at is... intent. What is the intent? Did PRS intend to deceive or confuse consumers by claiming that their guitar was a copy of a Gibson? Nope. Did PRS explicitly ride on the coattails (i.e., goodwill) of Gibson? Doesn't appear to be the case.
Did PRS say they bought a Gibson and measured every inch or it... dissected every part of it... and then proceeded to make a substantially out and out copy of the Gibson? Nope.
And the main thing that probably swayed the courts.... was PRS was not explicitly cashing in on the goodwill of Gibson.
msl