what you said is very true for the anti-bellum Midwest economy. What would happen, after secession, to the flow of goods up and down the Mississippi river is speculation.
Relatively sure the U.S. Government would make a strong attempt of collect tariffs where the Mississippi, Cumberland, Tennessee, and Arkansas rivers cross into the United States. Whether they could completely control the flow of goods out of the Confederacy to the Northern states is also speculation.
You said, “Relatively sure the U.S. Government would make a strong attempt of collect tariffs where the Mississippi, Cumberland, Tennessee, and Arkansas rivers”
Wouldn’t happen if you went to Charleston, paid for your import, loaded it, and shipped North. No taxes due on private property. Don’t think that would happen? See this:
The same week, The New York Evening Post wrote,
“Allow railroad iron to be entered at Savannah with the low duty of ten per cent, which is all that the Southern Confederacy think of laying on imported goods, and not an ounce more would be imported at New York; the railways would be supplied from the Southern ports.”
The Philadelphia Press said,
“Blockade Southern Ports. If not a series of customs houses will be required on the vast inland border from the Atlantic to West Texas. Worse still, with no protective tariff, European goods will under price Northern goods in Southern markets. Cotton for Northern mills will be charged an export tax. This will cripple the clothing industries, and make British mils prosper.
Finally, the great inland waterways, the Mississippi, the Missouri, and the Ohio Rivers will be subject to Southern tolls.”
That might just precipitate those surrounding states (excepting Illinois) into joining the CSA, which would also be a disaster for the North.