We had a dev working for the summer who got a job at an SF startup this past week. He's making $2k a week, but his rent for his apartment costs $3k and he's got roommates. As someone who has lived off of $40k and rented a $1.4k a month loft that was absolutely palatial, in the middle of the city with great views, this sounds like insanity. My coworker who is from the Boston area was similarly aghast at the differences in cost of living.
Have fun at your nice job, but I'm not coming home to roommates for $3k a month. The numbers don't really seem to work out, a lot of people are basically selling great living conditions for the chance to go work at companies that probably won't be there in a few years and really aren't doing anything interesting.
Also the "monoculture" dig applies to tech specifically: in terms of actual cultural diversity very few places are as interesting.
I feel like people who say this about any city haven't gotten out much in other cities.