Readers who don’t want to spend $30 for a new hardcover nonfiction book can no longer count on the release of a lower-cost paperback edition.

Traditionally, the paperback would hit the shelves about a year after the hardcover. Today, book publishers are printing fewer of them, closing a second-chance window for writers counting on a new cover or marketing campaign to spark sales. The shift reflects changing reader habits, the popularity of audiobooks and ebooks, and the power a few major retailers hold over the publishing industry.

“When I began in the business you could expect retailers to look at hardcover sales and order twice that in paperback,” said Gail Ross , a literary agent at William Morris Endeavor. “Now it’s just the opposite—half as much, at best.”

New adult nonfiction paperback titles tumbled by 42% from 2019 to 2024, to just under 40,000, according to Bowker Books in Print, a bibliographic database.

The number of adult hardcover nonfiction titles fell by 9% during that same period.

Publishers, authors, agents and retailers all earn more on hardcover titles than they do with paperbacks. The typical hardcover’s retail list price is about twice that of the paperback list price. And authors usually get royalties of about 15% of the hardcover price, but only about half that share on paperbacks.

Ian Buruma doesn’t have a paperback version of “The Collaborators: Three Stories of Deception and Survival in World War II.” It was published in hardcover nearly two years ago by Penguin Press and received warm reviews.

“Of course one wants one’s books to go into paperback,” said Buruma, who has written more than 20 books. “Publishers make their decisions based on commercial realities, and there’s very little I can do about it.”

Penguin Press declined to comment. “The Collaborators” has sold just over 1,100 hardcover copies, according to book tracker Circana BookScan.

Literary agent Andrew Wylie , who represents Buruma, said one factor in the shift away from nonfiction paperbacks is that Amazon.com , the country’s largest online bookseller, sometimes charges less for hardcovers than for new paperbacks.

In late February, for example, a 2023 hardcover copy of Jean M. Twenge’s “Generations: The Real Differences Between Gen Z, Millennials, Gen X, Boomers, and Silents—and What They Mean for America’s Future,” cost $18.69 on Amazon, while the new paperback edition, published in January, cost nearly $2 more.

An Amazon spokeswoman said the retailer compares and matches its prices to those of competing physical and online stores. “We work hard every day to offer customers low prices,” she said.

Barnes & Noble, the country’s largest bookstore chain , chooses one nonfiction paperback title to promote every month and buys “tens of thousands” of copies for each pick, said Shannon DeVito , senior director of books. However, she said publishers today are putting their emphasis on fantasy and romantasy paperbacks.

“If they were getting behind more great nonfiction titles, we’d carry them,” she said.

Some point the finger the other way.

“If retailers aren’t ordering the books at a high-enough volume to ensure some financial return, publishers won’t bother printing the paperbacks,” said Dan Conaway , a senior literary agent with Writers House.

For authors, it is a blow. “It’s profoundly demoralizing that a book that might have taken four years to write and was published with such promise is done after five months,” Conaway said.

Journalist Alexandra Robbins ’s book, “The Teachers: A Year Inside America’s Most Vulnerable, Important Profession,” sold more than 11,600 hardcover copies since it was published in March 2023, according to Circana BookScan. It was called “absorbing” by the Guardian and was deemed a New York Times nonfiction pick that season.

Many of Robbins’s earlier titles came out in paperback. “The Teachers” hasn’t.

Robbins referred questions to Dutton, the Penguin Random House imprint that published “The Teachers.” Dutton declined to comment.

Ross, the WME agent who represents Robbins, said “The Teachers” has sold just under 30,000 copies in all formats, including ebooks and audiobooks.

William LoTurco , an agent, asked Hachette Book Group recently why one of his author’s books didn’t get a paperback edition. The publisher said that there is no longer a “one-size-fits-all publishing model” and that it is responding to consumer demand.

Sometimes, paperbacks are postponed because the hardcover edition is so successful. Actor Matthew McConaughey ’s memoir “Greenlights” was published in hardcover by Crown in October 2020 and has since sold more than 1.5 million copies. The paperback followed a little more than four years later and sold about 167,000 copies.

“Online booksellers are significantly extending the life of the hardcover,” said David Drake , president of the Crown Publishing Group. The audiobook is also a hit; it ranked No. 4 on last month’s New York Times audio nonfiction bestseller list.

Nashville-based Turner Publishing now regularly publishes its titles in four formats simultaneously—hardcover, paperback, ebook and audiobook. Chelsea Henderson’s nonfiction book, “Glacial: The Inside Story of Climate Politics,” made its debut in hardcover, paperback and as an ebook on Aug. 6, with the audiobook following a week later.

“We want to make the biggest possible splash right away,” said Amanda Chiu Krohn , Turner’s managing editor. Although hardcover sales may suffer because some readers choose the lower-cost paperback, she said, total revenue per title is higher.

Henderson said she didn’t object to the publication plan. Still, she wondered whether her more lucrative hardcover sales suffered. “Even my sister bought the paperback,” she said.

Write to Jeffrey A. Trachtenberg at Jeffrey.Trachtenberg@wsj.com