SF hasn't been cool since probably the 90's.

People flock their, latch on to the manic imprint they burn into their mind in their first few years[1], and proceed desperately fight change. The infrastructure is wildly outdated, the social network can't support the excess homeless, and the building codes prevent the sort of compact, high-density living necessary to allow exactly the sort of lower-income people and families that everyone claims they want to keep around.

[1] as evidenced by my own comment about it not being cool since the 90's, though I think I could wrangle an objective argument out of it by looking at the explosion of housing prices, gentrification, and the sort of Urban Outfitter's commercialized uniformity of the modern "counter-culture".