Take for example the work of Print Mafia. When they create a print of John Lennon, I may be wrong but I don't think they're looking to pickup sales from Beatles fans. They use that image for it's iconic reference and cultural weight. It's not as much an homage to John Lennon in that regard. The message has been altered and become something more. To me that's when it gets interesting.
An excellent and thoughtful critique, now we're talking...thanks Andrew!
Also, I did talk to a lawyer regarding the SW themed posters I created.
This tread has become borderline trolling at this point.