Sure, but for the lower volume authors the royalties at year 20 are effectively 0. Most books don’t even sell out their first printing. Its a money grab to defend/prosecute copyright on a book that you couldn't even sell.

100+ year copyrights only help the descendants of the people that have already become extraordinarily wealthy. Cutting off at 2 decades would have close to 0 effect on the huge majority of creatives, while benefitting society immensely. JK Rowling would still be a billionaire, and small authors would be fine too.