Exactly. All one has to do is look at the various EV maps. Plus many of the farming states now have oil, gas and coal, i.e. ND, WY. The union hosses and bosses in NJ would be left trying to unionize dumpster diving in NJ, NYC because that would be their only source of income and food.
Also, as you mentioned, many former NYC/Wall Street companies already moved to DFW in the ‘80s and ‘90’s. So those willng to leave NYC or Chi-town would find it easy to do.
The "Blue States" are in fact blue harbor cities along the coasts and the Mississsippi river. If the secession occurs along state lines (unlikely) the Blue States will have more of the food. There isn't much growing in WY or ND or the intermountain West. It's about water. Not space.