A few interesting things with that. Just like in WW 2, they prolly would have started cranking out military equipment. Could be a power armor assembly line in Detroit for example.
I think it time to see some of these pre-war juggernauts have some form of plan for possible nuclear war by constructing their own bunkers/vaults. We always see posters and comments on corporate espionage, so let's have some.
For example, say Chryslus built regional office in DC area to spy on Vault-Tec and perhaps steal plans for Vault. Some people think that is actual corporate headquarters, but doesn't seem like it to me. Pretty small for a automotive juggernaut. I took it as more a regional hq. So, just to refresh my memory, I went there last night in FO 3 and there isn't a working computer in the joint, so absolutely no info, which imo is good cuz that means can do just about anything with them, and the corporate espionage could be good venue to take. Perhaps they pissed that GM and Ford game counterparts are getting military contracts. So they spying and scheming.
Could throw some factions at war from Chicago and Detroit, a great lakes midwestern power struggle with mwbos, slavers, and enclave thrown in the mix.
Vault 55 would prolly be a good vault to be in Detroit area. Perhaps 42 as well. Chicago could be a good location for a Secret Vault, and maybe Enclave caught wind of it and they are searching for it.