Sheryl Sandberg isn’t the first woman to realise that work in your 50s is no walk in the park | Gaby Hinsliff

Reaching 50 brings with it all kinds of unforeseen hurdles. No wonder so many women who can afford to are quitting altogether

Sheryl Sandberg is leaning out. The queen of can do" American feminism is quitting Meta (formerly Facebook) after 14 years at the top of one of the world's most powerful companies, for a future that sounds suspiciously vague. Apparently she wants to focus on feminist philanthropy, plus parenting our extended family of five children". (Having been widowed seven years ago, Sandberg will remarry this summer and will help raise her fiance Tom Bernthal's children plus her own two teenagers.) What happened, some wonder, to the woman who in her bestselling book Lean In urged other working mothers to just push themselves harder?

Perhaps she simply wants out of an increasingly toxic industry, accused of inadvertently fuelling hate speech, conspiracy theories and poisonous populist movements around the globe. For months Silicon Valley has buzzed with rumours that Sandberg, a committed Hillary Clinton supporter, was more troubled than other executives by social media's seeming role in the rise of Donald Trump, and that she was simultaneously losing internal arguments about its future. She stressed her closeness to founder Mark Zuckerberg in her resignation statement. But that won't stop speculation that she has had enough, and would rather spend the billions earned defending this morally sticky wicket on more uplifting causes. Her Lean In charitable foundation had, she said, never mattered more to her, given how critical this moment is for women", a nod perhaps to the gut feeling many American women have of hard-won female progress sliding into reverse.

Gaby Hinsliff is a Guardian columnist