Delivery drivers, hotel staff, fast food workers, teachers and thousands of other workers went on strike this summer, as did the people who play them on TV.

The Writers Guild of America walked off the job in May, and actors in SAG-AFTRA joined them in July. UPS narrowly avoided a strike by agreeing to pay big raises for full- and part-time workers. Unionized Starbucks workers struck at more than 150 locations earlier this summer as they tried to force management to negotiate a first contract. There were 177 work stoppages in the first six months of 2023, according to Bloomberg Law.

Experts say the recent uptick can be attributed to structural issues of inequality that were exacerbated by the pandemic, deteriorating working conditions, pay that has not kept pace with inflation and other factors. Meanwhile, companies have made record profits.

“The big deal is something that’s been a problem in the U.S. for centuries: The rich get rich and the poor get poorer,” said Art Wheaton, the director of labor studies at Cornell University’s School of Industrial and Labor Relations.

With unemployment rates at or near record lows, employees are emboldened to strike and have more leverage. And good contract deals can inspire others to act, said Susan Schurman, a professor at Rutgers University’s labor and management school.

At the same time, public support for unions is at its highest level since 1965, according to Gallup.