The vast majority of the people who have fled to the suburbs, especially north of 16 mile rd., were all auto company employees, both skilled trades and production whose incomes allowed them to purchase houses and properties not available in the city of Detroit.
Sterling Heights was the first haven for the new upper class wage earners from the auto industry and as that grew, they spread northword and the houses grew.
Macomb Twp., Utica and Shelby Twp. became the new destination of choice for the auto workers who had the incomes to build bigger houses in what was once wooded areas. Those areas are now filled with subdivisions.
The bottom line is, they left Detroit for the same reason anyone else does, a bigger house in a neighborhood that they can afford.....
Here in Eastern Jackson county, everybody works in Washtenaw County. Higher pay there, lower taxes here.