They will not deal with that problem and until they do no one is going to move there.
There's lots of automotive industry jobs in the Detroit area -- out in the suburbs. Go ten miles northeast of Detroit, to Grosse Point, MI and you will see lots of impressive multi-million dollar mansions
Middle/upper class people simply don't like living next to drug dealers who might want to burn out the neighborhood if they get disrespected.
Once Detroit reached the tipping point where the welfare class was the dominant voting bloc, the middle class moved out. You can see the pattern repeating elsewhere
..."that's the problem when a city relies on just one industry..."
Wasn't Detroit a single major industry-dependant city when it wasn't so much of a problem? Actually, the entire US and our allies in WWII were dependant on Detroit as it became known for it's mass production capabilities as the Arsenal of Democracy. What happened after that was an abuse of real estate sales practices and social climbing at the expense of the people left behind. What happened after that was a product of "liberealism" not The Renaissance. Today, there is still enough left to make a "killing" at the expense of the city's financial status.
Dietroit, Bethlehem, Buffalo all victims of "protections" provided to workers through the elevated status federal law has repaid to the trade union movement. Such "subsidies" to american enterprize encourages protection of profits through government, rather than encouraging innovation. GM is no longer an automobile manufacturing concern - it is a pensioner's bank whose voice will be heard in Washington for a long time to come. In the meantime, the law of comparative advantage will continue to unwind protected american industries.
I did not know that cities are the principal investors.
Like Palo Alto?