In fact, publishers had all sorts of ways to keep extending that license without our permission, keeping our own books from us for decades with minimal payment and no new contract.
But... Congress enacted a rule allowing artists of all kinds (Paul McCartney used this for his old songs) to regain the rights to their works after 35 years post-sale. There's now a five-year period where we can easily reclaim the rights to our own works.
You can learn more about that here:
Starting in 2013, authors began to have the ability to reclaim copyrights they transferred to a publisher in 1978 or later. Copyright law permits authors to reclaim their copyrights 35 years after transferring rights for purposes of publication. Authors interested in reclaiming copyright need to file a notice in advance, according to a designated timetable.
Reclaiming copyright allows the author to make new publishing arrangements, including making the work openly available on the web, or taking advantage of new economic opportunities.
Take back the rights! :)