Indeed, most movies make most of the money in the first few weeks of showing. Were it not for the physical limitation of having to go to a theater, much of that money won't be made.

Same with books: were it not for the need to buy a book before it shows up on libgen, or the need to have a physical book, book sales would plummet. Actually this is exactly what some of the anti-copyright activists proclaim as the goal: removing most of the need to buy a book, at least from the publisher.

Of course, there is the counter-example of music: people who pirate music also buy a lot of music, when the price is below the impulse buy threshold; see Bandcamp or Apple Music. The lack of copy protection does not incite them to pirate the same material, because they want to support their favorite bands. Those bands which did not sign up with major labels, of course, because the major labels earn and pay a significantly different amounts of money.