The only saving grace is the relatively short expiration of twenty years. if it was seventy years after the author's death progress would grind to a halt. IP e

The only saving grace is the relatively short expiration of twenty years. if it was seventy years after the author's death progress would grind to a halt. IP expiration dates are a "brain plasticity" parameter in society. Higher values mean lower rates of change, too low values mean too high rates of change. Twenty years is a sweet spot.