I would think a large pre-war city in ruins would kinda be a sign when passing over it that it could be a great place to loot. Ashur and Zimmer and such bragging and boasting about their might doesn't mean there isn't tons of loot in NYC, just means that they are maybe not some military strength that people have heard about. Assuming BoS is flying over it, they would get a pretty good look at a huge city, and thus potential loot haven.
CWBoS also isn't the WC BoS, and while I'm sure like anyone else they like high tech gadgets, they flipped on that mission.
Maybe they did stop, but I would think looting NYC would take a long time, which was my point to begin with, in with everything the CWBoS has on their plate, starting with rebuilding DC, seems like it would be many, many years before they moved on to other regions, especially if they making stops along the way.
But, I will agree, lets wait and see what happens, which has also been a point all along.