Can Marvel and DC just let some minor companies get away with the use? Does it really matter?
One of the problems with trademarks is that companies HAVE to defend the use of the term, or else risk losing the trademark protection. So if Marvel and DC began letting companies call their comics “Superhero ____,” they would risk a court ruling that the term was no longer protectable, which was the case for such famous words as cellophane and kerosene, both once product names, but ultimately became known as generic words that any company could use (The most famous company who vigorously defends their trademark is Xerox, who love to insist that you use a Xerox copy machine to MAKE a copy, not make a xerox!”).
