In time, I imagine sociologists will study the affects of such insular communities on empathy, happiness, and many other dimensions of the human experience.
I went to a local optometrist (who is surprisingly good); as far as I can tell, every patient who walked in was asking about Medi-Cal coverage or other government subsidy for the poor (which wasn't accepted, so they left). I'd far prefer to be around tech startup founders than the alternative, which is not "firefighters and teachers", but the poor and borderline homeless, it seems.
(I plan to move to Seattle or San Mateo County later this year; unclear if the benefits of Silicon Valley make up for the bogosity of California anymore.)
European, used to an upper middle class lifestyle; went to grad school in a poor USA state, then moved to Menlo Park, CA. Pretty big shock during both transitions.
Now living in Oakland while working in SF downtown, so things are a bit more even :)
There are way too many examples of what this leads too. None of them good. :(
I've gotten very used to mountain views, lots of sunshine and short commutes.
The best way to remind me of how good I've got it is to invite friends from out of town to visit.