Those developments complemented each other well. New fast-food investors wanted to rely less on owning restaurants, and offloaded many company locations to eager buyers who came with bags of cheap money from the banks. The investors could then count on a steady stream of franchise fees and royalty payments — buffers against overall sales declines if, say, the market ever became oversaturated. And they didn’t have to worry about actually operating the restaurants.

Franchisees pay for the right to operate a McDonald’s or a Subway, following rules that dictate everything from what type of taco to sell to where to buy iceberg lettuce. They take on the risks and costs of running the restaurants, in exchange for the marketing muscle and name recognition these big companies provide. While every Dunkin’ Donuts or Taco Bell may look the same, dozens and sometimes hundreds of independent owners can operate most of the restaurants within a single brand.

But some franchisees say they’re being pressured to open too many stores as food companies push for new revenue streams. Buying an existing restaurant, for example, may mean agreeing to build 10 new ones.

“They want us to sign aggressive development agreements,” said Shoukat Dhanani, the chief executive officer of the Dhanani Group, which owns hundreds of Burger King and Popeyes restaurants. “I didn’t see that even five years ago.”

The shuttering of restaurants could have a major impact on the labor market. Since 2010, restaurants have accounted for one out of every seven new jobs, and many restaurateurs complain that it has become increasingly difficult to hire and retain workers. In Muscogee County, Ga., a former textile center, the Labor Department reported an overall decline in employment of 2,000 jobs since 2001 — but a gain of 2,700 restaurant jobs.

Those positions could be in jeopardy if sales continue to fall and force more restaurants to close. Over the summer, the parent company of Applebee’s announced it would close more than 100 locations. In 2016 Subway, the nation’s largest fast-food chain by location count, closed more locations than it opened, the first time in its history that had happened.