It's the end of an era at Meta — and perhaps across the entire industry.

Sheryl Sandberg will leave Meta this fall after 14 years at the company “to write the next chapter” of her life, telling Fortune that she made the decision just this weekend. That timing is impossible to buy, but even if it’s true, Sandberg’s decision didn’t happen in a vacuum. The writing has been on the Facebook wall for years.

• For most of the company’s history, Sandberg was teflon. Whatever scandals the company faced — and there were many — they mainly landed at Zuckerberg’s feet.
• Sandberg maintained a glowing reputation as the rare female executive in a male-dominated industry and, with “Lean In,” created her own wildly successful global brand centered on women’s empowerment in the workplace.
• But Sandberg’s star began to fall along with Facebook’s after the 2016 election, particularly in 2018, when it became clear that she was as responsible for Facebook’s failures as she was its successes.
• Sandberg reportedly lashed out at Facebook’s head of security for investigating Russian interference without her blessing in 2017 and urged the company to dial back the details in early disclosures about the Russian intrusion.
• Facebook also reportedly hired an oppo research group to dig up dirt about George Soros’ ties to Facebook critics. Sandberg initially denied knowing anything about it, before finally admitting that she did.

Facebook’s pivot to Meta put Sandberg’s future in doubt. The last year at Meta has seen high-profile promotions and staffing changes.

• Nick Clegg rose to president of Global Affairs and the company created its first-ever chief business officer role for Marne Levine.
• With fresh faces to represent the company to both politicians and advertisers, the question became: What was left for Sandberg?

Sandberg’s exit is part of a more widespread changing of the guard. In just the last few years, so many of tech’s most successful leaders — Jeff Bezos, Larry Page, Sergey Brin, Jack Dorsey, to name a few — have stepped down from the companies they founded. There's a sense now that as the rules of tech platforms are being rewritten — by laws and by billionaires on ego trips — the people who built the last generation of tech giants aren’t going to be the ones building whatever comes next.

In her farewell announcement, Sandberg gave little indication as to why she decided her time had come and leaned instead on the old corporate cliché, writing that she plans to spend more time on philanthropy and family. But the reason for her exit may be the same as the reason she joined the company in the first place: Sandberg was Facebook’s first adult. Now, Facebook is all grown up.