Why are middle-aged men missing out on the job market?

Some economists speculate that the disproportionate decline could be because the age group has been hit by recurring crises, making their labor market fragile. They lost work early in their careers in 2008, faced a slow recovery afterward and found their jobs at risk again amid layoffs in 2020 and a continued shift toward automation.

“This group has been hit hard by automation and globalization,” said David Dorn, a Swiss economist who studies labor markets.

The fragility theory makes sense to Mr. Rizzo.

He saw the Navy as his ticket out of poverty in Louisiana and expected to have a career in the service until he broke his back during basic training. He retired from the army a few years later. Then he moved on to pivoting, earning a two-year degree in Georgia and starting a bachelor’s degree at Arizona State University—with dreams of one day working on a cancer cure.

Then the Great Recession hit. Mr. Rizzo had been working nights in a lab to afford the rent and studying, but the job ended abruptly in 2009. Phoenix was ground zero for the fallout from the implosion.

Frantic job requests came to nothing, and Mr. Rizzo was forced to drop out of school. Even worse, he found himself staring at impending homelessness. His tax refund saved him by allowing him and his wife to return to Louisiana, where jobs were more plentiful. But after the divorce, he hit a low point.

“I had nothing to show in my life after my twenties,” he explained.

Mr. Rizzo spent the next decade rebuilding. He worked his way through various corporate positions teaching himself skills in Excel and Microsoft SharePoint, remarried, had two sons and bought a house.

Still, he was regularly at risk of losing work to downsizing or technology — including late last year. The company he works for wanted him to move to a new job, perhaps as a traveling salesperson, when his desk job was gone. But his children have special needs and that wasn’t an option.