With his Fox News juggernaut minting some $2 billion a year in profit, 21st Century Fox CEO Rupert Murdoch probably isn’t fretting much over the loss of host Megyn Kelly to NBC. (Josh Reynolds/AP)

Don’t cry for Rupert Murdoch. Despite making a personal appeal and proffering bags of money, the billionaire mogul couldn’t secure the loyalty of Megyn Kelly, the second-biggest attraction of the most successful outpost of his multimedia empire, Fox News.

As announced Tuesday, Kelly will decamp to NBC for a very large payday, reportedly more than $20 million a year, and various high-profile roles. Fox moved quickly to plug the gap, naming veteran host Tucker Carlson on Thursday as her replacement at 9 p.m.

Murdoch probably isn’t too worried.

At the moment, Fox News is a money-printing operation, with profits approaching $2 billion a year. It wasn’t just the most popular news network on cable in 2016; it was the most popular of any kind on cable. It heads into the Trump era with a bloc of conservative-opinion programming so solid — call it the Big Republican Wall — that the loss of Kelly might sting, but the hurt is likely to be fleeting.

“The Kelly File,” after all, was just one brick in the Big Republican Wall. Fox had the 11 top-rated programs among cable news channels last year, and 14 of the top 15. One illustration of its viewers’ loyalty: The nightly repeats of Bill O’Reilly’s “The O’Reilly Factor” — the most watched show on cable news — pulled in more viewers than original airings of CNN’s signature program, “Anderson Cooper 360.” (O’Reilly, with 3.3 million viewers, also outpaces his colleague Sean Hannity by about 1 million viewers.)

(Erin Patrick O'Connor,Nicki DeMarco/The Washington Post)

That sort of success gives Murdoch — and his two heirs apparent, sons James and Lachlan — little incentive to tamper with the formula established by Fox’s founder, the defrocked Roger Ailes.

The elevation of Carlson to Kelly’s chair, in fact, looks like a doubling down on the status quo. Carlson has been at Fox since 2009, and when he took over for the departed Greta Van Susteren at 7 p.m. this fall, his ratings exceeded van Susteren’s in the time slot. (Carlson, in turn, will be replaced at 7 by Fox veteran Martha MacCallum, who will be the only woman to crack Fox’s evening lineup. MacCallum will host a Trump-centric news program called “The First 100 Days.”)

If anything, Fox may become even more pro-Trump without Kelly, who famously tangled with the president-elect during the campaign, said a senior executive at one of Fox’s rivals.

“This takes away the one person who at times — not always, but at times — was skeptical” of the president-elect, said the executive, who asked not to be identified, so that he could offer a frank opinion. “Now it’ll just be state-run TV.”

He added: “They have a deep bench. They’re going to be fine.”

Another executive at a Fox rival, who also requested anonymity, said viewer “momentum” is with Fox. “Trump supporters and Republicans in general are energized,” he said. “They want to watch a network that will support” the new administration. In fact, Fox extended its already sizable audience lead over CNN and MSNBC during the last week of December.

There’s still some question as to when Kelly can actually leave Fox. While her last “Kelly File” will air Friday, she remains under contract through July. Barring a negotiated exit before then, that means she’ll be off the air for seven months, and possibly longer. TV contracts typically come with “noncompete” provisions that keep stars from jumping to a rival until after a waiting period, sometimes for up to a year. If Fox plays hardball, it could put Kelly on ice for a long time.

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NBC News and Fox both declined to comment.

The biggest immediate beneficiary of the post-Kelly era at Fox may be O’Reilly, whose value to the network just increased. O’Reilly may not be unhappy to see Kelly go; he was indirectly critical of her in November for her blunt comments about Ailes in her recent memoir, “Settle for More.” But now he’s in a seller’s market with the Murdochs as he approaches his contract’s expiration at the end of the year.

A Kelly-less cable landscape could be a boon to MSNBC and CNN, if only temporarily, said another executive at a Fox rival. Kelly’s time-slot competition, Rachel Maddow on MSNBC and Cooper on CNN, stand to pick up some viewers who don’t warm to Kelly’s replacement at Fox, he said. “If someone’s ready to pounce on an open 9 p.m. time slot, it’s Maddow,” he suggested, somewhat optimistically.

Meanwhile, in a further shuffling of cable news personalities, Van Susteren, who left Fox in August in a salary dispute, will join MSNBC as host of a daily program at 6 p.m., NBC said Thursday.

As for Kelly and NBC, there’s risk. NBC has said it will feature her in a daytime talk show and a Sunday-night newsmagazine program, both to be determined. The former hasn’t worked well for other news personalities who have tried it, including Jane Pauley, Katie Couric, Cooper and Meredith Viera. The latter has a rocky track record, too; “Rock Center,” the ambitious newsmagazine fronted by Brian Williams, was canceled in 2013. In addition, any Sunday program on NBC has to wait for an unmovable object to vacate the scene: NFL games, which are locked into Sunday nights for at least four months of the year.

NBC sources say that’s not the whole story. An offshoot of the network’s “Dateline” franchise, “Dateline on Assignment” with Lester Holt, did reasonably well in a limited run last year.

And a daytime talk show? NBC already has the most popular and profitable one on television, the “Today” show. One non-NBC executive predicted that’s where Kelly will end up, hosting the 9 or 10 a.m. hour. It’s even possible that she would replace Matt Lauer, pairing with Savannah Guthrie in the first two hours of the program when Lauer’s contract expires in a few years, he said.

Either way, he added, with Kelly in the house, “I think NBC just protected the ‘Today’ show franchise for the next 15 years.”