Lots and lots and lots of dual-income lawyers and consultants. This is one of the areas where, on average, women have their first child at a very late age[1]. Lobbying across a wide array of industries but also defense contractors and such. I was actually just looking at median home sizes/prices[2] in that area for June of this year. I live in Arlington, bought a house earlier this year and discovered $425k is pretty much the bottom of the non-condo market, we only saw about 1 go up per month and everything closed immediately. Feels nuts here.
[1] https://www.nytimes.com/interactive/2018/08/04/upshot/up-bir...
[2] https://twitter.com/ConnorWaldoch/status/1070301922349981697