DETROIT (Bloomberg) -- The Motor City was the car capital of the world when David Cole graduated from a Detroit high school in 1955 and headed off to college to study auto engineering. Six decades later, the "motor" has mostly moved out.
Many of the factories that used to dot the city and employ thousands moved to suburbs, other U.S. states or to China and Brazil as the auto industry became global and manufacturing focused on getting faster and less expensive, said Cole, chairman emeritus of the Center for Automotive Research in Ann Arbor, Mich., and son of a General Motors president.
"The auto industry was forced to change, driven by industry pressure, and it evolved," Cole said. "Detroit did not. It's sad to see. We just took it all for granted."
Detroit, hamstrung by $18 billion in debt, was forced to file the largest bankruptcy for a U.S. municipality on Thursday. GM, Ford Motor Co. and Chrysler Group, the automakers that call the region home, are profitable and thriving.
"For much of the 20th century, the auto industry and Detroit were synonymous," said Harley Shaiken, a labor professor at the University of California at Berkeley. "You couldn't drive through Detroit but be aware of the presence of the automakers."
"The industry has become both global and very much decentralized in the U.S.," he said. "There's still a vital presence in Michigan and an important presence within the city, but their fates have diverged."
It isn't likely that Detroit's recovery will be as quick and easy as the turnaround of the U.S. automakers, said Steven Rattner, a New York financier who headed President Barack Obama's auto-industry task force in 2009 that ultimately put GM and Chrysler into bankruptcy.
GM and Chrysler were scrubbed clean of debt by U.S.-backed bankruptcies that lasted about six weeks. Ford suffered through a painful restructuring on its own that cut debt and labor costs.
"This will be much messier than the auto companies," Rattner said in an interview. "This will go on for a long time."
Detroit's ties to the fortunes of the auto industry have been fraying for six decades, as manufacturing jobs in the city fell from about 296,000 in 1950 to fewer than 27,000 in 2011.
The U.S. automakers, still ruling the road in the '50s and '60s, moved much of their manufacturing out of Detroit as they built new factories elsewhere in the United States and world. That evacuation of the city accelerated Detroit's decline.
Chrysler, majority owned by Fiat SpA, has factories to make Jeeps and Viper sports cars in the city and a 70-person office downtown, about 30 miles from the suburban headquarters where it employs more than 10,000.
GM builds the plug-in hybrid Chevrolet Volt at a factory in Detroit, where it also has its headquarters downtown. Ford, based in neighboring Dearborn, built Model Ts in Detroit until 1910 and hasn't built Ford cars in the city since.
The automakers each said Thursday that they will continue to play a role in the city as it restructures.
"The city has a difficult job ahead, and we are optimistic that governmental leaders will be successful in strengthening the community," Ford said in a statement.
"Chrysler Group believes in the city of Detroit and its people," the company said. "We not only continue to invest in the city and its residents by adding to our presence in Detroit, we also are committed to playing a positive role in its revitalization."
For GM, the filing may mark a "clean start" for the city.
"A healthy auto industry will play a part in Detroit's comeback story and GM is doing its part," the company said in a statement.
In an interview with USA Today, GM CEO Dan Akerson said the city's bankruptcy filing will have no immediate impact on automakers "from a financial perspective" but the stigma could make it harder to attract talent.
"Certainly it is something that future prospects will factor into their thinking: 'Do I want to move to a city that's bankrupt?'," Akerson said. "So the faster we get though this, and the quicker we rebuild, the better for the city and the state and for our industry."