Restaurant Associates is not the company it used to be. It has long operated restaurants, catered events and run corporate dining rooms for clients including Google and the Smithsonian Institution. Now it employs about half of the 10,000 or so people it had on staff before the pandemic.As its lines of business dried up, the company invented new ones. It has made soups and side dishes for the online grocer FreshDirect. It has delivered meals to displaced Wall Street traders working from Connecticut, and to guests attending “virtual galas” from home.Restaurant Associates is probably going to have to keep improvising. Just as things started looking up in the summer — with some museums reopening, businesses scheduling a return to the office, and catered galas bouncing back in full force — the Delta variant of the coronavirus brought everything, again, to a halt.“We were very hopeful that by September we would start coming back strong,” said Dick Cattani, the chief executive. Now, he said, “we don’t know what’s happening, what’s next.”This anxiety is widespread across the American economy. As Kevin Thorpe, chief economist of the commercial real estate services firm Cushman & Wakefield, noted, “The longer the virus lingers, the more transformative it is going to be.”A critical question is whether the urban service economy — the restaurants, hotels, taxi services and entertainment venues that employ millions of workers — can recover from the multiple waves of Covid-19 that have kept their customers away.After months of social distancing and remote work, this will depend to a large extent on how employers and workers readjust their attitude toward proximity and density — toward space.Three researchers — José María Barrero of Autonomous Technological Institute of Mexico, Nicholas Bloom of Stanford University and Steven J. Davis of the University of Chicago — estimate that from April to December 2020, half of the working hours in the American economy were supplied from home. After the pandemic ends, they think, the share will fall to around 20 percent. That is still four times the amount of work delivered remotely in 2017 and 2018.And remote work will be concentrated among the most highly paid workers in the most densely populated places. For instance, over half of the workers in high-skill, information-intensive services — in finance and insurance, information, professional services and management — were still working from home in January, according to researchers from Princeton, Georgetown, Columbia and the University of California, San Diego.Big cities face a dual threat of losing both their most skilled workers and the consumer service economies they sustain, the researchers wrote. “As a result,” the authors added, “they may shrink in size unless they manage to provide advantages that justify the costs of urban density when residential choices are set free from proximity-to-workplace considerations.”About 18 percent of office space in central business districts across the United States is vacant, compared with 12 percent before the pandemic, according to Cushman & Wakefield. Groupon, Twitter, United Airlines and other businesses are shedding office space. Some are rethinking their use of space entirely.Restaurant Associates, which has long operated restaurants, catered events and run corporate dining rooms, is working with about half of the 10,000 or so people it employed before the pandemic.Amy Lombard for The New York TimesAs its lines of business dried up, the company invented new ones.Amy Lombard for The New York TimesRestaurant Associates now delivers meals to guests attending “virtual galas” and Wall Street traders working from home.Amy Lombard for The New York TimesThe sports equipment retailer REI sold the corporate headquarters it was building in the Seattle area, meant to house some 1,800 employees, and is setting up three smaller satellite offices around the area, for workers to gravitate to if they wish. They can work entirely from home, too.“We felt there are moments when being physically together makes a difference but it doesn’t have to be all the time,” said Christine Putur, REI’s executive vice president for technology and operations. “We want to move forward with more habits, new norms — let the outcomes drive when and how we get together.”This reconfiguration of work is likely to reconfigure the American economy, changing wages and spending patterns.Google, for instance, is allowing employees to work remotely. But it will adjust compensation depending on the local cost of living. In a blog post to employees, Google’s chief executive, Sundar Pichai, estimated that some 20 percent of them would choose to work from home permanently. And the company developed a calculator for employees to figure out the effect on their pay.Mr. Davis of the University of Chicago and his co-authors estimate that the increase in working from home will reduce spending in city centers by 5 to 10 percent, hurting business at restaurants, bars and other spots that rely on the spending of office workers.“Some of the leisure and hospitality activities will follow those people that are no longer in the downtown area,” Mr. Davis said. But the spending of newly suburbanized workers may be different, including fewer lunches and happy hours than when they worked downtown.America’s economic geography looks different from what it did two years ago. New York City’s share of the nation’s employment fell to 2.8 percent in July 2021, from 3.1 percent in July 2019. That means about 375,000 fewer jobs than if the city had at least kept pace with the country as a whole. More