Copyright lasts until 70 years after the death of the author. That has nothing to do with protecting the author, but protecting the publishers. Is it a good idea for heirs? No, why should heirs of an author receive money for work they didn’t create? Give enough money to living authors then they can entail something.
What about the lots of media that are out of print? You must not copy them until 70 years after the dead of all of their authors. Ridiculous, isn’t it? The only reason for this rule is, that publishers want to assert full profit should they once decide to re-publish old work. My opinion: If something is out of print, you cannot harm the profit and thus a work should become public domain.