I don't know if it's a big city thing, but it definitely is a DC thing.
I relocated after living in several different cities in the south (including VA) to the DC area, and it was shocking to me that, for a large number of people here, keeping up with the Joneses is definitely a way of life! And not just in smaller ways to which I was accustomed (maybe designer purses or upgrades to a house), but full-out luxury european cars, crazy expensive cigars & wine, etc.etc...
Always wondered why some of my relatives who moved to DC early in life became obsessed with status and things they perceived enhanced that status, but after living here I understand that they felt this huge pressure to fit in and gave into it.
I'm older, and don't plan to change my ways to this lifestyle (and can't afford it anyhow
I think younger people may be under more peer group pressure, but I would live life the way you want to live it and to heck with those who may want to pressure you to do otherwise. I suspect some of those young people may be "trust-fund babies" who have access to more funds than a normal person and others who are trying to impress them. Lots of both groups around DC.