I believe you have that exactly backwards. In 1860, the South payed 75% of the costs of running the Federal Government, and they employed the vast bulk of the Northern Shipping fleet in carrying their goods to Europe. 200 Million per year was flowing through the New York economy precisely because of the Tariff's and shipping laws instituted in Washington DC.
If the South were permitted to become independent, not only would all this money be lost to New York and Washington DC, the additional revenues achieved by cutting out New York and Washington could have been used to build competing industries in the South.
A Lot of Wealthy and powerful men stood to lose a great deal of current and future revenue if the South was allowed to trade directly with Europe outside of their control.
So my point here is that the North East very badly needed a war with the South precisely because of economic reasons. If they ever allowed the South to have direct economic trade with Europe, many of their industries would have been badly damaged economically.
It needed the economic engine of the South to survive, so forced the South back into the United States of America,
This is incorrect. The "economic engine" of the South was slavery. Once you have eradicated that, you have no "economic engine" in the South that could produce the same profits it did pre-war. This is one of the reasons why the South became mostly impoverished after the war.
What the North did was say "If we can't have that economic engine, we are going to make sure nobody can have it." For the first two years of the war, they were going to keep slavery. It was only after they realized the South would not stop fighting, that they decided to destroy slavery.
Washington and New York originally wanted the slave based money system in the South to continue. They just wanted to make sure the money circulated through their hands. When they saw that the money was going to stop, that's when they decided they had to have a war.
I never thought much about the true cause of the Civil War, but your argument makes a lot of sense to me.
And it shows the Deep State was already in high gear back in 1860. And Abraham Lincoln was really a 19th century Mitch McConnell.