The social structures of almost all large US cities through the 50s and early 60s were still largely de facto segregated, with a great deal of racism in key institutions, i.e. police forces. Detroit was almost 50% black by population, but the police force was about 85% white and was dominated by highly prejudiced enforcement activities and attitudes.
In most US cities, a transition to less segregated housing and shopping patterns and much less racist law enforcement was successfully implemented during the 1960s, but Detroit wasn't so lucky, and had the 1967 Riots. Prior to the Riots, Detroit had the highest US-large-city rate of black home ownership, and was making excellent progress on black household net worth due to the availability of good jobs. That all began to unwind after the Riots.
Some amount of movement to the suburbs had begun in the 50s, as middle class and well-off families--mostly white, although there wasn't a racial theme to the pattern--chose to move to new communities that offered new larger homes on larger properties with new schools and new civic infrastructure. This existing movement became a flood after the Riots, particularly among middle class families that lived close to parts of the city that were affected by the Riot destruction. The Riots began a period of turmoil in the Detroit public schools, with many black youths rejecting guidance and leadership by whites and more importantly in many cases rejecting learning itself and the standard curriculum as inherently "white" and therefore illegitimate, with commensurate increases in school violence and breakdown of discipline, and this turmoil and breakdown of educational effectiveness was a further motivation for "white flight".
Jerome Cavanaugh, the Mayor during the Riots, was widely considered to have been discredited and chose not to run again. Roman Gribbs, the next Mayor, was well intentioned, but the problems were beyond his ability to manage. Coleman Young realized for the 1973 elections that Detroit could elect him, its first black mayor, if black turnout was high, and he successfully achieved that and was Mayor for the next twenty years.
Young's blunt racially based approaches reversed some of Detroit's issues, but the schools remained troubled; neighborhood decline, housing stock deterioration and housing value decreases accelerated because of unfixed Riot damage and social turmoil plus poorly planned "urban renewal" and withdrawal of neighborhood infrastructure funding to support major construction projects around the downtown area; crime continued to increase from the increases during the Riots; racist attitudes on all sides corrosively influenced every aspect of politics and social interactions; and "white flight" became a widespread phenomenon. Retail businesses that had provided shopping for the city's prior population, in many cases adversely impacted since the Riots, broadly went out of business or, in a few cases, moved to the suburbs. The loss of retail and distribution jobs from the city further aggravated the ongoing loss of manufacturing jobs in the metro area as the Detroit auto industry contracted due to its uncompetitive cost structure and inadequate quality. Drug use in the city increased dramatically, in conjunction with the rise of several competing primarily-black street gangs that were heavily involved in various criminal activities, and competitive interactions between those gangs resulted in significant increases in the murder rates. Unemployment, and particularly black unemployment, increased dramatically.
