"Detroit" moved to the suburbs. Check out the statistics for Oakland county (and possibly macomb county for the blue collar workers).

Toyota, GM, Ford, Chrysler, Nissan, VW, and all their parts suppliers(and the supplier parts suppliers) have at minimum a white collar office in south east Michigan.

The event that caused the Exodus from Detroit was the Race Riots. You can Google that because I'm not touching that topic.(and it doesn't help Detroit has a 1% tax)

Most people I know would choose to live in a temperate climate with low humidity if they had the option. Detroit might have been economically useful due to certain modes of travel and location of population at the time, but that may not be relevant anymore.

>"Detroit" moved to the suburbs

Similar thing can happen to SV. People moving to "suburbs" -> other parts of CA.