Does it sound fair to someone who has never created a single patentable invention in his life? Or written a best-selling novel? Or composed a symphony? Or written a screenplay?
It sounds plenty fucking fair. Architects & engineers don't get paid royalties for years & years on work we did ages ago. We certainly don't continue to get paid after we're dead. And if we fuck up, things fall apart. People can get hurt. People can die. If a screenwriter fucks up, nothing of any consequence happens.
I'm sure it does sound fair to parasites who think they are entitled to other people's work without compensation.
If you did the work 20 years ago, tough shit. Welcome to the world of everybody else.