My personal example or experience: I would love to live in SF or in Alameda county. My employer statewide pays same salary to everybody with same title, with SF county (not Alameda) getting extra $260 per month, whereas rental differece is like $1000 for studio in non-Alameda & $2500 in SF.

Many of my colleagues can still afford to live in SF because they have their parent's homes or something in that area, and thus pay no rent, or have way lower expenses in housing.