Life of the author seems potentially too short. What if an author is struck down early? Shouldn't their family left behind be able to enjoy some of the profits for a period of time?
As you suggest, a time-based copyright term (such as the original Copyright Act term of 14 years with a single renewal) would preserve this incentive even for authors who expect they might die before the end of the term.
It doesn't take copyright to make a profit off of a work. the Criterion Collection includes Charade, which is out of copyright: https://www.criterion.com/films/603-charade
I'm sure the children of the author can come up with inventive ways of selling the work.