Millions of Americans are gravitating toward a new way to subscribe to streaming services — and tech, media and cable companies are lining up to take advantage.

Facing a chaotic maze of apps, payments and passwords, people are increasingly signing up for multiple streaming services through a single provider.

Amazon, by far the leader in this growing trend, urges users of its Prime Video service to sign up for and watch HBO Max, Paramount+ and other services through its app. Apple, Roku and YouTube encourage the same — as do cable providers like Comcast.

The number of new subscriptions purchased through one of these third-party apps has jumped 40 percent over the past two years, according to research from Antenna, a subscription research firm. Nearly 30 percent of all new subscriptions are bought this way.

Signing up directly — like through a company website — still remains the most popular way to get a new streaming subscription. But the sudden popularity of signing up through a third party signals the emergence of a new kind of cable bundle, a development that media executives have predicted for many years but that had not yet become much of a reality.

The shift could help reshape the consumer experience. Viewers can go to one platform and find a single interface with shows and movies that are available on a wide array of services, or channels. It also has set off a fight between media, tech and cable companies to try to be the dominant one-stop shop.

“You could almost call this the next chapter of the streaming wars,” said Jonathan Carson, the chief executive of Antenna.

“The winners of that battle will effectively become the equivalent of what the cable providers were for the linear era,” he said.

Consumers have complained for years that the streaming era requires them to hopscotch from one app to the next to get a sense of what to watch. Amazon said 77 percent of its viewers wanted their streaming apps consolidated into one place, according to customer research the company did in 2023. (That finding gave Amazon “more conviction” to pursue this strategy further, said Albert Cheng, the head of Prime Video in the United States.)

For media companies, the development has major trade-offs.

Making their streaming service available at a third-party retailer helps defray millions of dollars in marketing and technological costs. Most of the companies have labored to make their streaming services profitable in part because of those costs.

But platforms like Amazon take a big cut of the subscription revenue, often 30 to 50 percent, along with a piece of the advertising revenue. This route also cuts off the direct relationship between a media company and a subscriber.

For some companies — particularly Netflix, which has by far the most subscribers, with about 300 million globally — that has been reason enough to mostly avoid selling subscriptions through third parties. “Netflix already operates as a go-to destination for entertainment thanks to the breadth and variety of our slate and superior product experience,” the company told investors last year. Disney, likewise, has largely been sitting on the sidelines.

For more niche services, however, the popularity of signing up through a platform has been a boon. Specialty streaming services like Crunchyroll and BritBox have eagerly signed up, which helps drive subscriptions and awareness to brands that are not well known.

And then there are players with considerably bigger budgets that are joining the fray. After years of selling only directly, Apple TV+ joined Prime Video’s channels environment late last year. The number of new subscriptions to Apple TV+ has grown since then, with Prime Video already responsible for 29 percent of new sign-ups, according to Antenna.

“It promotes a lot more subscription trial and activity and discovery in a way the app store environments don’t,” Mr. Carson said.

YouTube started its channel business only a few years ago (under the name YouTube Primetime Channels), and the company already is a “huge believer in this business,” said Jen Chun, the head of sports and studio partnerships at YouTube.

“What we have heard over and over again from folks is that they don’t like having a lot of different apps to click in and out of,” she said. “It is messy on their screen, it is challenging, there’s a certain level of inertia that people have, particularly in living rooms. Folks really just want to turn on the screen and watch.”

Roku’s president of subscriptions and partnerships, Gil Fuchsberg, said its channel business had grown considerably over the past year. He called it the “fastest-growing part of our subscriptions business.”

But the market leader is, by far, Amazon Prime Video.

Amazon Prime users have signed up for 46 million streaming subscriptions via its channel business, significantly more than Roku or YouTube, according to the Antenna data.

The company has had the benefit of doing it for a long time — it started a decade ago — but it was only in the last few years that executives there and elsewhere began to realize its power.

In 2021, HBO Max no longer made itself available on Amazon Prime Video. Overnight, HBO Max lost 5.1 million subscribers, according to Antenna data.

But eight months after those subscribers left, fewer than 500,000 of them had elected to resubscribe to HBO Max, according to the data. When HBO Max returned to Prime Video in late 2022, more than three million of them signed up within three months, according to Antenna.

“I think it became very apparent how we were contributing to the overall streaming marketplace with HBO coming off and back on,” said Mr. Cheng, the Prime Video executive. “That’s when you kind of go, ‘Oh, yeah, we actually do make a difference.’”

Mr. Cheng said Prime Video drove new subscriptions “that would have been difficult for our partners to get on their own.”

It has been Mr. Cheng’s job to persuade would-be partners to think of Prime Video as a helpful aggregator of programming.

“There are a lot of people who prefer to be in a place where they can consume all of it in one place,” he said.

Mr. Carson, the Antenna chief executive, compared the changing attitudes to Nike’s decision a few years ago to pull out of retail shops in favor of selling directly to the consumer. That strategy failed, and Nike has begun selling its sneakers in stores again.

“There are many people that are going to DSW to buy a pair of trainers, and if Nike’s not on the shelf, then Nike’s not getting that sale,” he said.

Mr. Cheng said he wanted consumers to start seeing Prime Video more and more as a “marketplace for streaming,” arguing that being a retailer is precisely what the company has long been good at.

“Our job is we want to be the best at selling stuff,” he said.