Chicago has one gigantic advantage over Detroit: it is the largest rail transportation hub in the USA. So much so every railroad is spending huge sums of money to upgrade the rail lines in the metropolitan Chicago area to expedite goods transport through the city. And Chicago has a vibrant financial sector, expecially in commodity futures trading.
Yes, but Detroit had the largest industry in the country for seventy five years. The auto industry. They basically left, as can commodities and rail lines. As more and more people become displaced, or even stagnant in place due to economic malaise, the rail lines and commodities exchanges will find a better home. They can leave just as easily as automobile production.
Look at the unfunded liabilities of all government levels in this country and to conclude that a terrible fall is all but inevitable.