A Detroit-specific reduction in federal taxes would obviously be beneficial to the city; how beneficial would depend upon the details.

However, that isn't ever going to happen, because who outside the area would vote for it? Instead, the most you would get would be a set of areas around the country which met some criteria for economic distress which would get a tax break. Once you start expanding the areas covered, the revenue losses become large as companies go tax-shopping and you can't offset them so the size of the tax breaks falls and you get a nothingburger.