The trouble in setting up there would be, what are you going to use for a workforce?
You think there is a lack of a willing and capable workforce in Detroit Metro? You could not be more wrong. There are reasonable reasons to pick places other than Metro Detroit to build a factory but the blight in Detroit City and perceived lack of a workforce is not among them. Honestly I can't think of many better places to build a factory if you really look at the evidence. The opportunity is definitely there. You might find cheaper labor elsewhere but you aren't going to find a more capable labor force anywhere for manufacturing.
Likely as not, not locals
You bet. There is more manufacturing and engineering talent in Detroit metro than all but a handful of places in the US. Did you forget that GM has their headquarters in downtown Detroit? Where do you think they get their people from? Do you think it is by accident that almost every single car supplier of consequence has engineering operations somewhere near Detroit? Michigan ranks 4th in the nation in high tech jobs. Metro Detroit is the second largest source of tech jobs of any metro area in the US. If you want manufacturing talent you could do a lot worse than Michigan.
So yeah, the locals will do just fine.
how are you going to convince folks to me to Detroit, not much incentive to move to a barren, economically sparse, drug infested/violence infested area.
If you think that properly describes all of Detroit then you aren't wanted there and you clearly know little about the area. Downtown Detroit near the Renaissance Center has actually seen a pretty nice revival. Not to say the city overall doesn't have a long way to go (it very much does) but there are big parts of it that are nothing like the hell hole you are describing. Guys like Dan Gilbert are buying up all kinds of property and businesses are setting up shop left and right. It's a hell of an economic opportunity if your investment horizon is sufficiently long term. There are three major stadiums, a convention center, a university, three casinos, GM, outstanding restaurants, Whole Foods, and lots more all downtown. You really think Whole Foods is going to set up shop in the middle of a blighted, drug infested area? I just had a relative open up an upscale coffee shop in Downtown Detroit and another relative of mine has a fast casual restaurant at the Renaissance Center.
Furthermore it doesn't have to be in Detroit City. The Detroit Metro area is genuinely nice. I live in Oakland County which is immediately to the north of Detroit City and is one of the ten wealthiest counties in the entire US, has a AAA credit rating and is a genuinely nice place to live. Washtenaw and McComb counties are equally nice places. The University of Michigan as well as several other excellent local universities provides an outstanding local talent pool.