COL is a terrible indicator. 1/3rd COL isn't really 1/3rd. If you have a large family the requirement of a large house/apartment will make your cost of living much worse in SF than 3x - while if you sleep in your car and cook on a camp stove your COL is the nearly the same in both places (car registration might be slightly more in CA). Both are extreme cases, but they get the point across.
While I would expect a somewhat lower salary outside of SF, it wouldn't be 1/3.