What ended up happening, though, is that as factories shuttered, the neighborhoods that were built around them started to collapse. The net result was pockets of localized decay, that eventually led to the entire urban area rotting as more people left. It's actually kind of stunning to see in person. (I live about 50 min South of Detroit). And oh, the riots of 1967 didn't help, either.
It's hard to imagine that happening the the metro-Bay area, but I remind myself that people once thought GM, Chrysler and Ford could never go under.