The change had already occurred.

[wausaubob]

The railroads had already changed the US economy by 1860. The deep south had gone all in on cotton, and sugar, and cotton was at that point, primarily an export crop.
There had been a large decrease in oat production in 10 years between 1850 and 1860 in the southern states.

And the same pattern existed in Missouri and Kentucky.
They were not growing their own oats, as they were moving rapidly to reliance on mules as work animals. Since railroads and steamboats could supply each section with whatever the other grew, each section could specialize.
It wasn't odd for the far south states to think they were different, in some ways, from the rest of the US. What was odd was them thinking that as an independent country they would have been immune from economic pressures exerted by international lenders.

 

[wausaubob]

Aggregate statistics make it seem like there was a mild imbalance in manufacturing capacity. But looking at the statistics by industry reveals that about 4.3% of the rolled iron capacity of the US existed in Virginia as of 1860.

That does not mean that the Confederates cannot win a war. But it does mean that even a minimally effective blockade is going eliminate the Confederacy's ability to find competitive prices for sufficient rolled iron to maintain its railroads. It probably means there was no plan to win a prolonged war, because such a plan was nearly impossible.

 

[wausaubob]

Then there are indicator industries, like steel.

Steel was not an important industry in the US. But if all the steel production is located in the Mid-Atlantic states in 1860, it means every knife, scissor, scaple, saw and steel axe head, acquired by the Confederacy, is going to have to run the blockade. And the blockade runners, operating out of Edinburgh and Liverpool, can charge whatever the want for such items.

 

[wausaubob]

Locomotives were a key product of the northern industry.
They don't last long under 1860 conditions. Here is where they were manufactured in 1860.

And train car wheels are about the same:

 

[wausaubob]

The simple facts were that in a war fought on a continental scale, with railroads present in the territory of both belligerents, railroads and population were going to control both the original mobilization and the ability of each army to maintain its fighting forces. It was nearly certain that in the early battle for the 5 border areas and Washington, D.C., the US would greatly outnumber the Confederates and win these early contests, even if they were tactically defeated, which they were.
This, combined with the huge advantages of the US in ship ownership, ship building capacity and international naval manpower, meant a short war was nearly impossible.