Because intellectual community is extremely hard to get. Unless you're moving to Ithaca, it's hard to find a place that is full of interesting people and ideas. This pushes you in ways you wouldn't get in places like Buffalo and so on - the culture of a city like San Francisco or Boston is full of smart people with a certain background (i.e., people who are interested in tech) who can stimulate you. You're far more likely to overhear a conversation about Claude Shannon or minimum spanning trees in SF than you are in Buffalo.
Absolutely not, I agree; I'd just say that "interesting" varies widely with the context. If what you're interested in is running a tech startup, Detroit is less "interesting". There are many, many terms on which San Francisco is less "interesting" than the rest of the country.
Huh. Never lived in Ann Arbor or Detroit, just visited/had friends and family who lived there. My impression of Ann Arbor is that it's a college town where the population is relatively insulated from the surrounding community, unlike Boston where the colleges are heavily connected to local industry and so on. Everyone I've known from Detroit is an activist of some kind, so I probably have a biased sample set. But based on that I'd say "no", whereas I would definitely lump Cambridge in with Boston or Berkeley/Oakland in with SF.
