Draconian Mickey Mouse copyright law has likely stifled more innovation that we could possibly imagine. Much like patent law there should be a strict, non-renewable period where a company can recoup their cost and make profit. Then it is introduced to the public domain.
Not “allowing people to play NES games for free” is rent seeking, innovation stifling behavior that extends far beyond simple NES games.
Further, why shouldn’t I be allowed to share a game I rightfully own? If I do not own it, then I lease it. If I was not made aware of that then it is fraud. The ethics are simple: When buying is not owning, piracy is not theft. Simple as that.