The money went with the jobs. Automation has been changing auto manufacture, and trucking made it possible to make parts a long way away, and still serve the factories.
New Orleans is the same, losing population since 1950. The docks went to containers, the banana boats went to Gulfport, the forturtune 500 left for Texas, and Disney wanted to open a park here, but ran into a place more corrupt than Florida.
Flint, Toleato, Cleveland, all the same, Union wages lead to Public Employees becoming Union, and cops, firemen, water, making six figures, plus pension, medical, over the last 40 years.
Pensions balooned, while housing decayed, and jobs left due to high taxes and Unions. 30 years on the job, retired at 48, will live another 30 to 40 years.
At least New Orleans has tourism, no one wants to see old Detroit after dark.
It is happeneing everywhere, pensions figured on people living to 67. or 72, and 87 was never even considered.
Also the people retired, first from public jobs, were the war babies, a huge population spike. It changes the ratio of retired to workers, which used to be seven to one, to two to one. This continues for another forty years.
When George Bush took office oil was $13, now around a $100. Running a city, heating buildings, fueling vehicles, gargabe trucks, public transit, costs a lot more.
Detroit is as abandoned as New Orleans east after Katrina, Abandoned and not paying taxes, but some left so police, fire, emts, keep working.
Neither city can afford to tear down the abandoned property. People are still leaving, so redevelopment would not work.
Ibn Khaldun documented the process in 1300, how all governments before his time had fallen. Shrinking taxes, growing costs, everything in disrepair.