Er... guys, your American states are as large as European countries (the largest ones being in the range of France, Germany, Spain down to UK, the smaller ones in the range of Switzerland down to Belgium). As bit less populated (and even that is not really a drawback since it typically means more available resources per inhabitant), but otherwise... why wouldn't they be able to support themselves? Furthermore, having different governments/countries does not block the flow of goods.
Imagine a European country...
a lot of space right?
Now imagine it's in the middle of a desert. Literally.
OK, do you have that picture in your head? Great!
Now... imagine that it's ALSO landlocked.
If you've followed along to this point, then I want you to answer the following question in as honest a fashion as you can:
How many, "resources per inhabitant", would that nation realistically have available?
Continuing with our thought experiment, imagine there was no federal government to provide the structure for, say, Texas, to share its energy resources with other states...
now, ask yourself why Texas would continue to give Idaho free energy resources? Should Texans continue the charitable practice, in exchange for a few Idaho potatoes? There are just better markets for those resources. And I wouldn't blame Texans one bit for availing themselves of the opportunities those markets present.
Governments, and common sense, can, and do, block the flow of goods.
What I'm trying to point out, is that I don't think you've thought this whole thing through.
But then you just replaced one government with another. Worse, the one you replaced it with has fewer abilities. How does it get fuel for logistics. (ie - the food pantries get food from where? The federal government is gone, so the oil tankers don't dock anymore and the pipelines aren't full anymore.)
Sure, Chicago would be golden, it's on lake Michigan. But what happens if you live in Arizona? Where does your water come from?
Who helps if a hurricane guts Miami FL?
Who helps if a tornado guts Norman OK?
Etc etc etc.
Our way of life just doesn't support hyper local governments doing whatever they want, and hording resources from other hyper local governments. We, for better or for worse, are set up on the premise of bountiful energy, and through that energy, bountiful access to resources. That's just how we survive currently. No one has the stomach or the constitution to go back to being local farmers.