Surely you have a reputable source for this claim? Other than "my friends pirate them." Because I know for a fact that there are some indie NES and SNES games being made today, along with rom hacks, and those are legal.
Emulators exist for other reasons. Sure, there are people who do use them to pirate, but then we come back to the knife/car argument. Besides, what about all other emulators? You keep bringing up the NSW because it serves your argument, but it falls apart when you bring up dead platforms.