A rather standard strategy for the Democrats appears to be run up the vote in the cities while making inroads in the suburbs and basically ignoring the rural areas. Populations in major counties with sizable populations have either been shrinking or growing at a rate slower than the state as a whole across the midwest. Wayne, Cook, Cuyahoga, Allegheny, Milwaukwee, and Hamilton Counties along with Philadelphia have had their populations either shrink dramatically, e.g. Wayne County, or exhibit growth that is slower than the state as a whole, e.g. Milwaukee.
How bad does this hurt the Dems? Does it simply off-set rural population loss? Wayne County has lost almost a million residents since 1970 and that is with a Michigan population that has seen an increase. Since Dems are so reliant on city voters, how bad could this hurt the Dems in Michigan in the future where the population loss of Detroit is poised to continue?
Well if the trump wins Michigan in 2020 by 2.5 points then we can safely say that Wayne county is what will kill the democrats in Michigan same in Ohio and Illinois