Netflix, Amazon Prime Video, Disney+ and…Pluto TV?

Viacom boss Bob Bakish is betting big on a little-known startup to compete among a fast-growing crop of video-streaming titans — but media insiders wonder whether the millennial viewers he’s targeting will have any time for it.

Under Bakish, the owner of MTV, Comedy Central and Nickelodeon shelled out $340 million in March for Pluto TV, an ad-supported service that has streamed everything from repackaged CNN segments to old episodes of “Roseanne.”

Days after the deal was announced in January, Bakish called it “a true game changer” that will help free Viacom from its reliance on cable TV, which continues to get slammed by cord cutting.

That’s despite that, when Viacom announced the Pluto buy in January, it was logging a yearly revenue rate of just $100 million and was not profitable, an insider told The Post.

On its second-quarter earnings call last week, Viacom Chief Financial Officer Wade Davis said Pluto has increased its monthly user base to 16 million, up from 12 million, since January — and he claimed that the streaming service is a “billion-dollar opportunity.”

This month, Viacom began loading up Pluto with its own content — including binge-worthy marathons of MTV’s “The Hills” and Nickelodeon’s “SpongeBob SquarePants” reruns.

Short-term, the strategy is to offset Viacom’s plunging viewership on cable. In the fourth quarter of last year, Viacom’s audience across its cable channels plunged 13%, according to Nielsen.

Nevertheless, experts are skeptical about whether Pluto is going to shake up streaming in the years ahead. Given the scant barriers to entry in the niche, Pluto’s price tag looked “healthy,” said Dave Morgan, CEO of Simulmedia, a targeted TV-advertising company.

“This is a deal with question marks,” Morgan said. “I’m sure the acquisition gives Viacom some speed to market. Maybe it signals to everyone they are in it. I think the challenge is that there’s a limited amount of consumer viewer bandwidth.”

Video streaming will get increasingly “crowded” in the next year, as new services from Disney, Apple, WarnerMedia and NBCUniversal hit the Web over the next year. He added that consumers can only sit and watch so much, making Pluto’s continued rate of growth challenging.

Meanwhile, Pluto’s profits are squeezed by its “middleware” business model, Morgan said. In addition to sharing revenue 50-50 with content producers like Bloomberg, CBS, Sky News and NBC News, Pluto pays fees to distribution platforms like Roku, Apple TV and Amazon Fire TV.

“It’s a sustainable model if you don’t overpay for content,” according to a source with knowledge of the business.

That said, whether or not Pluto is a huge success isn’t as important as the role it plays for Viacom, says Alan Wolk, co-founder of video consultancy TV[R]EV.

“It’s a way to reach people who are often unreachable with TV,” Wolk said.

“The smartest argument for the value of TV is you remember TV commercials you’ve seen 10 years ago,” he added. “You don’t remember a banner ad you saw 10 seconds ago.”