I agree with virtually everyone when they say San Fran. Chicago (the city) is reflexively Democratic and San Fran is reflexively liberal... so as long as the Dems are the liberal party... then, yeah. But, yes, the issue is the suburbs. The San Fran suburbs are filled with wealthy, educated liberals... the Chicago suburbs are very middle-working class, white ... and prone to swing to the GOP.
The elitism your party manufactures about who its voters are is truly amusing. The wealthiest people in Chicagoland are the ones who make the suburbs "GOP-friendly," SOMEWHAT offsetting the legions of poor people who make the city unwinnable.
This ^ is not the kind of post one should make while throwing stones about 'elitism'.
Oh, and to OP, SF for sure.