They really don't, especially not anymore. For-profit book publishing has turned decidedly Hollywood. I've worked in both book publishing and in Hollywood, and people often forget that they are really one in the same now. CBS owns Simon & Schuster, HarperCollins is owned by News Corp, and Penguin Random House is owned by Bertelsmann, one of the world's largest media conglomerates.

How are they different? They both support long copywriters, support DRM of digital media, etc.

Two important ways: first, they're happy to publish physical, analog books, which the movie industry no longer does. That allows institutions like libraries and used-book stores to exist. Second, they've never put a rootkit in their DRM.

Realistically analog books are harder to copy and distribute than digital books. Some authors won’t publish to kindle for that reason. (https://www.quora.com/Why-isnt-Cracking-the-Coding-Interview...)

The movie industry also creates physical disks that you can trade but they have had copy protection since the analog era.