I don't think there's an overabundance of people making $250k around here. That's still a lot of scratch. But if you have dual incomes, a household income of $250k is pretty commonplace in DC and the surrounding suburbs.
As far as living with my family...f that
My parents live back in Chicago where I'm from, my sister lives in NYC and my brother lives in San Francisco. We couldn't live together if we wanted. I've lived by myself for the last four years and with a roommate for a number of years prior to that.