Just to understand, you are saying that a property you fully control from ages 20 to 76 will leave you a pauper, but if you extend it for 14 more years you will not? If it's that big of a deal, what happened to the money made during those 56 years?
Let us consider the case of Peter S. Beagle - Hugo and Nebula Award winner, holder of a World Fantasy Award for Lifetime Achievement, and SFWA Grandmaster. You'd imagine that with such under his belt, he should be raking in cash from his work.
The man wrote one of his most popular works,
The Last Unicorn, back in 1968. It was made into a movie, with a script he wrote himself, in 1982. Unfortunately, the company holding the contract from 1999, withheld
every red cent of the money due to him. It took eight years of legal battles to get a settlement. And then... his manager then screwed Beagle again, tying up not just
The Last Unicorn, but most of his other work as well. That only resolved in 2019.
And, by this law, he'd lose rights again in 2024.
Most creators are not legal powerhouses, and can lose decades of livelihood in legal disputes. In having a mad on for big businesses, it is more than possible to stomp all over individuals.