In the 1960s, the auto companies and their suppliers generated an estimated 300,000 jobs in the city. Now the number has shrunk to less than one-tenth of that.

“Detroit’s fate is the result of decades of job flight,” said Thomas J. Sugrue, a professor of history at the University of Pennsylvania and author of a book on Detroit called “The Origins of the Urban Crisis.” “The auto industry has been decentralizing since the 1950s, first to the suburbs, then to small-town Midwest and Sunbelt, and later elsewhere in America and overseas. The city of Detroit is now only symbolically the Motor City.”

And auto jobs are continuing to disappear. Last year American Axle and Manufacturing, a major supplier to General Motors, closed an ’80s factory complex that as recently as 2007 had 2,200 workers. The company transferred the work to a lower-cost plant in Mexico, and now plans to demolish its Detroit site.

The carmakers still have a large, visible presence in Detroit. Chrysler operates an assembly plant and three smaller factories on the east side, as well as a branch office downtown. G.M. has its corporate headquarters on the riverfront, and an assembly plant that straddles Detroit and the neighboring city of Hamtramck. Ford has no operations in the city, but some of its suppliers are there.

Since the government bailed out G.M. and Chrysler in 2009, both companies have recommitted to building vehicles for the long term in Detroit. Chrysler has added two shifts at its highly profitable Jefferson North plant, and recently introduced a new version of its strong-selling Jeep Grand Cherokee sport utility vehicle. G.M. assigned the Chevrolet Volt plug-in hybrid and several other models to its assembly plant to keep it busy for years to come.

Yet the two automakers employ fewer than 10,000 white-collar and hourly workers in the city — with less than half actually residing in Detroit.