You can't be serious. Are you saying that, sitting on a civil jury hearing a lawsuit at some future date, you'd conclude that Mario - one of the most recognizable fictional characters in the world - is no longer a trademark of Nintendo because a third party made a C64 clone of the game?
I don't understand how you view this as the likely outcome. Nothing even close to this has ever happened ever.
> Quite simply, the view that a trademark holder must trawl the internet and respond to every unauthorized use (or even every infringing use) is a myth. It’s great for lawyers, but irritating and expensive for everyone else. And when done clumsily or maliciously, it chills free expression.
https://www.eff.org/deeplinks/2013/11/trademark-law-does-not...