https://www.theatlantic.com/national/archive/2011/08/arlingt...
Also the DC metro system is in fact organized across state lines and receives generous federal subsidies....DC Metro spends $4.7 billion a year. There's also interstate light rail from MD and VA to DC that's billions more. There are probably few cities in the world that have public transport more heavily subsidized than DC.
Commuter income tax reciprocity in DC metro is no different than most other regions.
The primary issue this week is that this section of Virginia rarely sees snowstorms of this magnitude and further most DC residents have no idea how to drive in it (or know when to stay home).