Meta, the owner of Facebook and Instagram, went on federal trial a few weeks ago. Some 47 states had accused it of marketing addictive and harmful products to young people.

It was an all-encompassing courtroom assault on the social media powerhouse. Meta, valued at $1.47 trillion, warned it might be on the hook for $1.4 trillion.

That is real money, even in Silicon Valley. Since Meta had already lost or settled several social media cases this year, critics and commentators started to wonder: Was this social media’s Big Tobacco moment, a historic occasion when a once-popular pastime gets kicked to the curb by the combined judgments of regulators, courts and activists?

On Wednesday, Meta settled with the states. It will pay up to $17.1 billion over a decade and change its social media properties to make them less compulsive for young people.

The sum of $17.1 billion is rather less than $1 trillion. Those hoping for the end of social media as we know it and the downfall of Meta’s chief executive, Mark Zuckerberg, were vocal in their disappointment. “This penalty is minuscule when you consider the wealth & power behind Meta,” Public Citizen, a consumer rights group, complained on Bluesky.

If social media critics did not get their Big Tobacco moment, historians said, that might be because they were chasing a myth. The Big Tobacco moment was never very big.

In 1998, state regulators came together in a deal with the four Big Tobacco companies. In the so-called Master Settlement Agreement, those companies agreed to pay more than $200 billion (more than $400 billion in today’s dollars) over the next quarter century, stop marketing to youths and make other changes.

It was the largest consumer settlement ever. Smoking has been in decline ever since. Thirty years ago, teenage smoking was routine, sometimes even cool. More than a third of young people had the habit. Now smoking zones in high schools have gone the way of chalkboards and audiovisual carts.

In 1999, there was a big Hollywood movie that secured the settlement’s legacy. “The Insider,” starring Russell Crowe as a besieged cigarette company whistle-blower, cast the struggle against tobacco in highly dramatic terms. The movie was widely acclaimed and is still celebrated.

But the struggle against cigarettes was in general rather less cinematic, tobacco historians said.

“The Master Settlement Agreement was in the interest of the tobacco companies,” said Louis Kyriakoudes, director of the Albert Gore Research Center at Middle Tennessee State University. “They bought themselves out of significant litigation and were allowed to go forth and do business.”

Robert Proctor, a Stanford professor and the author of “Golden Holocaust: Origins of the Cigarette Catastrophe and the Case for Abolition,” was more caustic.

“Today is not the beginning of the end for social media, any more than 1998 was the beginning of the end of Big Tobacco,” he said. “Americans still smoke more than 170 billion cigarettes every year, and inhale tons of additional nicotine from ‘electronic’ variants. How easily we forget!”

Dr. Proctor was interviewed as he sat on an airplane waiting to fly to a Big Tobacco trial in which he would serve as an expert witness. The cases never stopped, he said.

To the extent that Big Tobacco had a downfall, it was decades in the making, said Sarah Milov, author of “The Cigarette: A Political History.”

“The Meta of 2026 is better off than the Big Tobacco of 1998,” she wrote in an email. “By 1998, tobacco — and, more specifically, smoking in public — had been under social and legal assault for more than a quarter century. The Master Settlement Agreement wasn’t their wake-up call. For decades, activists had mobilized to make smoking and, to some degree, smokers socially unacceptable.”

Urged by activists, municipalities first limited, then banned, smoking in public places, she noted. Corporate America came onboard. Smokers were increasingly framed as bad employees: They got sick, ruined equipment, took too many breaks.

The campaign against social media is nowhere near this widespread, nor this successful.

Nevertheless, Ms. Milov wrote, “it strikes me as significant in a time when Americans cannot agree on basic facts that they can find consensus on regulating Meta.”

“This demonstrates, perhaps, a shared agreement on the utter failure of Congress to address the harms of social media,” she added.

Mr. Kyriakoudes, who is working on a history of cigarettes, said that the states’ deal with Meta this week might be a largely symbolic victory, but that symbols mattered.

“One thing that recurs periodically in American history is a deep hostility to large, concentrated power centers that seem unresponsive or uncontrolled,” he said. “That happened to cigarette companies, and seems to be happening to social media companies.”

Taken as a whole, the recent string of social media setbacks in court is one of the biggest legal defeats for Big Tech since a federal judge in 2000 ordered Microsoft to be split up for antitrust violations. The breakup ultimately didn’t happen, but the near-death experience scarred the company for years.

Meta encouraged the Big Tobacco comparison in a legal filing last month that said the tech giant might be liable for $1.4 trillion, about the value of the whole company. Meta arrived at that figure by multiplying millions of users by per-use violations.

“A sanction of that size has no analog in the history of consumer protection enforcement,” the company protested.

While certainly one of the largest settlements ever with a single company, $17.1 billion is a glancing blow for one that made $60 billion in net profit last year. “Meta will always choose to pay, rather than to fight, because then it doesn’t have to change,” Anil Dash, a tech entrepreneur and critic, wrote on Bluesky. Investors immediately pushed up the price of Meta shares, indicating that they saw few long-term consequences.

The effects are hard to know, however. The tobacco settlement required the release of industry documents that implicated the companies, which in turn further cut their political support and inspired new claims against them.

There’s no equivalent requirement in Meta’s 2026 settlement, but the lawsuits have already brought forth damning documents. One reason that social media may eventually end up as ostracized as cigarettes, at least for teenagers, is that Meta employees have explicitly equated the two products internally.

“Oh good, we’re going after <13-year-olds now?” one Meta employee wrote in a document cited in at least one suit. The employee added that “targeting 11-year-olds feels like tobacco companies a couple decades ago (and today). Like, we’re seriously saying, ‘We have to hook them young’ here.”

Social media companies are rapidly changing, even without the goad of lawsuits. Meta wanted for a few years to be a virtual reality company. Now it wants to be an artificial intelligence company. What exactly this will entail, even Meta doesn’t know. But it is happening with alarming speed.

Antonio Nieto-Rodriguez, an expert in project management and focused organizations, said he worried that social media companies would not learn the real lesson of all these lawsuits: that their product was working exactly as they had hoped. They want it to be so compelling that it is compulsive. It is the dream of every marketer introducing a new product.

The problem is, that has now become a liability. With A.I., the same risks are multiplied. No one even pretends to know what the long-term effects of the technology are.

“A.I. is being deployed into products, decisions and human lives faster than any technology in history. Same playbook: optimize for speed, ship first, govern later, measure what’s easy,” Mr. Nieto-Rodriguez wrote this week in a post on LinkedIn with the headline “Social Media Just Had Its Tobacco Moment. A.I. Won’t Wait 15 Years.”

He added, “We are, right now, writing the internal documents that someone will one day read aloud in a courtroom.”