No one can "fix" Detroit because no one can even discuss the reasons why Detroit is Detroit. It's not Democrats (Seattle and the Bay Area are fine). It's not big companies (there do happen to be auto plants in other areas). It has to do with the great unmentionable taboos of modern American society.

To state why Detroit is Detroit is like saying that "Stalin was a dictator" in 1970s Russia[1]. It doesn't matter that the leaders[2] of the society acknowledged that as fact, or even that everyone knew that it was true on some level. You yourself can't state the truth about why Detroit is Detroit. Like in the 1970s USSR, you won't be shot, you will just probably lose your job and/or be forced into a public apology.

[1] http://www.volokh.com/2010/04/30/on-a-bus-in-kiev/

I remember very little about my childhood in the Soviet
Union; I was only seven when I left. But one memory I have
is being on a bus with one of my parents, and asking
something about a conversation we had had at home, in which
Stalin and possibly Lenin were mentioned as examples of
dictators. My parent took me off the bus at the next stop,
even though it wasn’t the place we were originally going...

What’s more, this is so even though most people, including
most Communists, knew that Stalin was of course a dictator.
The government itself had acknowledged as much. Even Lenin
was widely understood to have been a dictator in the sense
of someone who didn’t govern through democratic means.

But it’s not the sort of thing that you’d want to say in
public, or even to your friends in private. Sssh! — people
might hear! Those who hear might draw deeper inferences
about what else you might believe. This might get back to
the place you work. You might be fired, or blacklisted. By
the 1970s, you probably didn’t have to worry much about
being shot, or being sent to Siberia; these were not the
1930s. But lost jobs, ruined careers — sure. And a forced
public apology: well, of course, that might help a bit.

[2] http://www.washingtonpost.com/politics/president-obamas-rema...

Now, this isn’t to say that the African-American community
is naive about the fact that African-American young men are
disproportionately involved in the criminal justice system,
that they are disproportionately both victims and
perpetrators of violence. It’s not to make excuses for that
fact, although black folks do interpret the reasons for
that in a historical context.

We understand that some of the violence that takes place in
poor black neighborhoods around the country is born out of
a very violent past in this country, and that the poverty
and dysfunction that we see in those communities can be
traced to a very difficult history.

And so the fact that sometimes that’s unacknowledged adds
to the frustration. And the fact that a lot of African-
American boys are painted with a broad brush and the excuse
is given, well, there are these statistics out there that
show that African-American boys are more violent -- using
that as an excuse to then see sons treated differently
causes pain.

I think the African-American community is also not naive in
understanding that statistically somebody like Trayvon
Martin was probably statistically more likely to be shot by
a peer than he was by somebody else.