The advantages I've had by moving from Arkansas to here have been numerous, and mainly this is due to human nature causing companies with enough co-located employees to leave remote workers out of the loop.
The OP is right though: I find the "herd effect" that occurs from a bunch of very similar people especially potent in SF. What's funny is how diverse they think they are based on superficial traits like maybe ethnicity, but the reality is they tend to be very uniform in socio-economic background, age, and education.