I don't disagree with your critiques and I certainly have my own of the area, but I see a lot of that as an argument for why the Arlington corridor is part of DC conceptually. It is highly connected to DC (transit times into DC as low or lower than many intra-DC trips), high density (the entire county is only a bit less population dense than DC itself), and essentials are walkable if a bit inconvenient at times. Arlington would be a bad city if it were isolated, but Arlington is the way it is because it isn't isolated.
