200 million dollars per year in 1860 dollars was easily enough to trigger a war, and as i've explained to you and others previously, the financial losses to Lincoln's backers were going to be even worse than that.
European goods were going to flood the Western territories due to the greatly reduced import tariffs. The manufactures in the North East would have lost those customers .
If the Confederates had put their tariffs up around 40% like the Union, they would have probably been allowed to leave in peace. The North wouldn't have perceived it as a great reduction in their trade profits, and may have left the South alone.
“European goods were going to flood the Western territories due to the greatly reduced import tariffs”
Only by smuggling. The U.S. Government has a right to collect tariffs on goods entering it’s territories from foreign countries. Legally traded goods from the Confederacy would have had to have the tariffs paid on them plus the importer into the Confederacy would have had to pay the Confederate tariff. This double tariff on goods would give the Northern manufacturers an advantage, their goods would be cheaper because they didn’t have to pay the tariffs.
The fight was to preserve the Union and had almost nothing to do with financial concerns.
As you note many Northern businessmen knew they would lose if a war was fought.
Just like today the larger cities were pro-Confederate.
Those goods would have been taxed twice. Once by the Confederacy and once by the Union. So they would not have been any cheaper than domestic manufactured products.
Moreover, you've got a very skewed view of things. Ohio and Illinois were industrializing. They couldn't and wouldn't rely wholly on farming to provide for their people. So a flood of foreign goods wouldn't be any favor for the growing industrial workforce of those states and others.
If the Confederates had put their tariffs up around 40% like the Union, they would have probably been allowed to leave in peace. The North wouldn't have perceived it as a great reduction in their trade profits, and may have left the South alone.
You contradict yourself. Was it the loss of tariff revenue or the coming flood of foreign goods that so angered the Yankees? Was their government going to collapse because of the loss of tariff money, or where they willing to live with that but only upset about some more distant developments?
I think both scenarios are wrong and foolish, but the new one may be even wronger and foolisher. As it was, the Union survived the loss of the cotton trade and so did the Northern manufacturers. That manufacturers would actually want neighboring countries to impose high import tariffs on the products they make is something so self-defeating as to be nonsensical.