On a sidewalk once lined with food carts, a lone hot-dog vendor stood one recent Friday on a corner below the building. His name is Ahmed Ahmed, and he said he used to sell 400 hot dogs a day.

How many now? “Maybe 10.”

Midtown Manhattan, the muscular power center of New York City for a century, faces an economic catastrophe, a cascade of loss upon loss that threatens to alter the very identity of the city’s corporate base. The coronavirus’s toll of lost professions, lost professionals and untold billions of lost income and tax revenue may take years to understand and resolve.

Other neighborhoods are rushing to reopen, while Midtown remains stuck in a purgatorial Phase Zero, its very purpose — to bring as many human beings together as possible — strangling most hope of a convincing comeback in the foreseeable future and offering a sign of what may lie in store for business districts across the country.

Upstairs, floors are mostly empty, as companies reassess their need for office space, raising serious questions about the future of the city’s commercial real estate market. Downstairs, streets were lined with the creature comforts that made working in Midtown not only bearable, but even fun. They are vanishing, and with them, the men and women who fed, clothed, poured drinks for and drove the people in those tall buildings.

The Men’s Wearhouse below the former Time & Life Building, now named 1271 Avenue of the Americas (its address), remained boarded up for months. The store reopened early this month, its role in offering and tailoring custom business and formal attire perhaps never less relevant.

The staffs of the steakhouses were furloughed months ago. Mr. Ahmed, the hot dog vendor, looking over what should be prime real estate outside Radio City Music Hall at West 50th Street, said he was thinking of cutting back to every other day.

Subway data tells a story as stark as Mr. Ahmed’s cart. Take the Rockefeller Center subway station, a major stop for four train lines and the point of entry and exit to the neighborhood for workers from all over.

Last year on June 24, a Monday, there were 62,312 MetroCard turnstile swipes as riders entered the station. On the comparable Monday this year, June 22, the number of swipes was 8,032, a staggering 87 percent decrease.

In jeopardy of extinction, at least in its known state, is the corporate office culture at large — its corner suites and cubicles, water-cooler movie reviews, coffee breaks, office crushes, shoeshines, black cars. Happy hour, “Mad Men.”

That show was set in part in the Time & Life Building, which lent a shorthand nod to corporate chic. Today, the story of the state of Midtown can largely be told with a close look at the block near Rockefeller Center where it has stood for more than 60 years.

“The Time & Life Building set the new standard, transforming the west side of Sixth Avenue from a collection of old tenement-like buildings into a corporate corridor,” said Robert A.M. Stern, the modern traditionalist architect whose firm has executed many prominent projects in Manhattan and around the globe.

He was not a fan, especially not of the way the building was set back from the street, a departure that became standard practice on Avenue of the Americas, as Sixth Avenue is also known. “It celebrated itself,” Mr. Stern said. “It was in the era of the glamour of corporations.”

The Rockefeller Group, the building’s owner, emptied 1271 Avenue of the Americas for significant renovations shortly after Time Inc. moved most of its operations downtown in 2015. The building reopened last year, and the law firm Blank Rome, a longtime tenant in the Chrysler Building eight blocks downtown, was among the first to move in.

Among the first lawyers through the door was Martin Luskin, who has spent 41 years with the firm. His biggest fear, looking across the street at Rockefeller Center, was the holidays ahead.

“We were petrified, hearing stories about the tree lighting, and the weeks before and a couple of weeks after,” he said. “But in the end, when you get used to it and see the excitement in the families bringing their children to see the tree, the excitement takes over. It’s an energizing effect.”

He would grow fond enough of Rockefeller Center that he became a member at the Rainbow Room, the gilded and mirrored destination for Champagne brunch and chandeliers on the 65th floor of 30 Rockefeller Plaza (“30 Rock”).

“A client lunch or client drinks in the evening — that’s my spot,” he said.

Now, his spot is his home in Westchester County, staring at clients on his screen instead of alongside breathtaking views in Midtown. The Rainbow Room remains closed. The means of arrival and departure that made the Rainbow Room unique — the long elevator ride — would seem to be a possible liability if a day comes when cars can carry only four diners at a time.

His colleague Deborah A. Skakel, also working from home, said she had found herself missing her own Midtown rituals. She recently paid a brief visit to the office and noticed a favorite food cart, called King Tut, missing. “You could get a gyro or souvlaki, but what I got was salad on the bottom and grilled chicken and sautéed vegetables,” Ms. Skakel said.

She would carry her humble meal to a little office park with tables and a waterfall under trees.

Both Mr. Luskin and Ms. Skakel showed optimism that Midtown would rebound, just as it has before, from high crime, financial crises and the 9/11 attacks, which struck fear in many people working in tall buildings.

But in the short term, those buildings are preparing reopening protocols that will bear very little resemblance to life before the pandemic. Before returning to the office, employees will watch videos that lay out the new world: masks, temperature checks, contact tracing questions, a maximum of four to an elevator, with arrows on the floor pointing at the corners. Employees will essentially make reservations to enter the building, with a computer rejecting new arrivals after the maximum number is reached.

At street level, the block that once thrived on the appetites and expense accounts of the people above has wilted.

The Capital Grille was a popular destination for business lunches and dinners and drinks — an “upscale, old-fashioned, kind of clubby steakhouse,” said a bartender who has worked there for the past 11 years.

Starting in the early afternoon, patrons would enter under a portrait of Henry R. Luce, the legendary editor of Time, and linger at the bar for drinks before heading into the dining room for dinner. “Then a nightcap,” said the bartender, who declined to be named because the restaurant did not authorize him to speak. “‘Oh, we’ll have one more while we’re waiting for the car.’ They’ll drop another three hundred, four hundred bucks on a corporate card.”

The restaurant furloughed all its tipped employees: the wait staff and bartenders. It closed for four months and reopened for sidewalk dining in early July. A lone waiter served six tables along West 50th Street, with no portrait of Mr. Luce in sight.

The emptying out of Midtown has had a profound impact on the Executive Plaza, which opened in 1986 at Seventh Avenue and West 51st Street in what had previously been the Taft Hotel. Its more than 400 apartments, rented out to companies based in the area, including The New York Times, have been temporary homes to countless employees, executives, trainees, foreign correspondents visiting their home bases and Broadway performers — including the Rockettes and Santa Claus — needing a short-term place to stay.

But since the city shut down in March, many of those corporations, with no one traveling, have not renewed their leases. So the building has pivoted, persuading the owners of the apartments to cut rents for a new kind of tenant.

“Young people, millennials, whose leases are expiring elsewhere, and they’re looking for deals,” said Susanne Miller, the leasing agent for Executive Plaza. “They want to not be on the subway. They want to walk to work.”

Mr. Stern, the renowned architect, said the past was a hopeful indicator in this uncertain time.

“New York survived the late ’70s, and everybody thought the city was over, rampant crime, near bankruptcy,” he said. “It survives the market crashes of ’87 and ’89, it survives the dot-com crash of 2000 or so. It survived 2008. So it will survive. But each time, each one of those moments probably can be traced in relationship to new ideas on how to occupy existing buildings or how to occupy new buildings.”

Daniel A. Biederman, executive director of the Bryant Park Business Improvement District, said that for the sake of the neighborhood’s very identity, Midtown executives who fled the city to work remotely should feel a moral purpose to come back as soon as safely possible.

“They’ve almost made the unpatriotic decision for Midtown Manhattan,” he said. “We need them back.”