Bill O'Reilly, host of the eponymous The O'Reilly Factor on Fox News, has held the top spot in cable news for 15 consecutive years. Averaging 3.29 million viewers a night, O'Reilly easily scored first place in cable news show viewership last year, crushing 8 p.m. rivals Anderson Cooper (in 17th place with 1.14 million viewers on CNN) and Chris Hayes (in 19th with 1.07 million viewers on MSNBC).

But is the king about to be cast from his throne?

Over the weekend, The New York Times published a bombshell report: Since 2002, Fox News has paid a whopping $13 million to settle several claims that O'Reilly sexually harassed and threatened the careers of multiple women.

As of Thursday morning, more than 40 companies had pulled their ads from O'Reilly's show, Axios reported. The exodus includes such big names as Mitsubishi, Lexus, BMW, Hyundai, Credit Karma, T. Rowe Price, Allstate, and Mercedes-Benz. In their public explanations, many of the companies cited the allegations against O'Reilly as inconsistent with their values. (Meanwhile, President Trump defended O'Reilly: "I don't think Bill did anything wrong.")

In the past, O'Reilly has said the sexual harassment allegations against him have no merit, and that he and Fox News are being targeted because of his fame. But O'Reilly did not respond to the latest story on either his Monday or Tuesday night broadcasts, and his spokesman declined to comment to the Times.

All this should be enough to make the brass at Fox News nervous: Advertising revenue is the economic lifeblood of most any cable show. Freakouts by advertisers ended the runs of radio host Don Imus at NBCUniversal and of Glenn Beck at Fox News.

At the same time, O'Reilly's show is easily the network's single biggest revenue generator, hauling in around $446 million in advertising money from 2014 to 2016. Fox News dominates competitors, and provides one-fifth of the profits for 21st Century Fox, making it the parent company's single biggest profit source. So it would take an absolutely enormous exodus of advertisers to bring O'Reilly down. Beck's departure came only after he was abandoned by hundreds of advertisers, for example.

Many of the companies pulling their ads from O'Reilly are merely shifting to airtime on other Fox News shows, meaning the scandal poses little threat to the bottom line of the network as a whole. Fox could decide to keep O'Reilly on out of sheer pique. In fact, O'Reilly's contract, which pays him $18 million annually, was set to be renewed this year. Fox News already extended it, despite knowledge of the multiple settlements and the complaints against their star host — though "people familiar with the matter" did tell the Times that the new language includes "more leverage over [O'Reilly's] behavior."

In some ways, this is part and parcel of the difficulty boycotts have in changing the behavior of their targets. Even planned boycotts have a hard time succeeding. And so far, O'Reilly's travails are not the result of a planned boycott — just a spontaneous cultural panic in reaction to general outrage.

However, if the advertiser retreat does become a more coordinated and intentional affair, its chances of successfully torpedoing O'Reilly's show would go up. There's already some evidence that could happen: Groups like the National Organization for Women, Color of Change, and the folks who put together the Women's March are already calling for advertisers to drop O'Reilly's show, or for Fox News to drop O'Reilly.

Boycotts often succeed when raw economic leverage dovetails with a broader cultural change in attitudes and values that hurts a brand's reputation. (Remember in 2001 when a boycott forced Nike to issue an internal report admitting it had employed child labor in developing countries?)

O'Reilly's scandal looks like a case of the cultural shift already being in place, or mostly in place.

To explain: Fox News was already reeling well before these O'Reilly revelations. The first blow came when 21st Century Fox was nailed by a phone hacking scandal that engulfed its media outlets in Britain. Then another string of sexual harassment accusations forced out Fox News' chairman and CEO Roger Ailes. After that, executives promised a new company culture "based on trust and respect," which makes the sting of the latest scandal all the more sharp. Oh, and the network is also being sued by a handful of employees for racial discrimination.

Throw in shifting viewer demographics, and Fox News might have a real problem on its hands. "The median age of a prime-time Fox News viewer in 2015 was 68, according to Nielsen, older than at both its main rivals," Jennifer Saba wrote in the Times. "To keep the momentum going […] the networks will have to find younger viewers."

Courting younger viewers means placing a higher premium on fighting sexism and racism. Younger viewers are far less forgiving of the swaggering mid-century patriarchal ethos that Fox News seems to indulge in. The job of updating the network has fallen to James and Lachlan Murdoch, as their father Rupert Murdoch slowly steps down from his role at the top of 21st Century Fox. And there have indeed been renewed efforts to encourage Fox News employees to come forward about inappropriate behavior.

O'Reilly wields enormous clout. But all of the pieces are in place for this scandal to rapidly snowball into something much larger.

O'Reilly may still be the king of cable news. But the king is wounded. And everyone knows it.