Welcome to San Francisco, shrinking city. By now an old story, both the urban core and the metropolitan area are domestic migration losers. Less known is the problem of natural decline:

Families that remain in The City are bucking the trend that has plagued San Francisco for years as the number of children — defined as people up to 17 years old — has dropped from 181,532 in 1960 to 107,524 today, according to the latest U.S. Census Bureau figures. The 2000 census counted 112,802 youths.
That's over a 40% drop in young children, something you'd expect to find in the Rust Belt. A few years ago, San Francisco formally studied the crisis. The results reveal a similar demography for Portland, Oregon:
While Portland, Oregon has a child population slightly higher in proportion to the national average, Portland has struggled to retain families, despite affirmative efforts to do so. From 1990 to 2003, the city added more than 90,000 people, growing to an estimated 529,121 residents. According to demographers at Portland State University, the number of school-age children grew by only three between the census counts in 1990 and 2000.
Relatively better off, Portland isn't on par with San Francisco as an immigrant destination. Immigration glosses over how people are voting with their feet and fleeing the Bay Area. At a minimum, the urban core is in a state of steep natural decline.
Detroit best keep that in mind the next time someone laments that Hockey Town isn't more like San Francisco. And what the hell is Governor John Kasich babbling about?