Correlation != causation. The reason for all those things is because the auto industry failed to adapt to technology changes, leaving a huge hole in a place that was used to having a lot of affluent workers. That means the barbershop stops getting customers, so does the grocery store, etc.
I imagine silicon valley could look just like detroit if all of the sudden all the companies just hit "pause" and stopped building new cool things.
The auto industry got its butt handed to itself by Japan's innovative manufacturing techniques.
To blame the democrats exclusively for what are clearly economic woes is not accurate at best, and misinforms others, at worst. If republicans are great, we should celebrate the places where they actually are great, instead of taking pot shots at loosely correlated facts, and viewing the democrats as "the other guys, who clearly are morons." Democrats often do the same to republicans, which is actually just the politician's way of getting what they want: Dehumanizing the other guy