More of America's poor now live in the suburbs than the cities:
https://qz.com/1001261/american-poverty-is-moving-to-the-suburbs/
Cities everywhere are undergoing gentrification, and housing prices are rising considerably.
So it's an interesting question, but it should look at a whole region and not just the District. I expect the affluent will remain within 5-10 miles of the city, and poverty will grow in places like Gaithersburg, Rockville, Laurel, Burtonsville (I don't know Virginia at all though).