The problem with your theory is that it was the South which chose to initiate "an appeal to arms." The CSA had been very precisely informed that Ft. Sumter would be forced to surrender in a few days anyway for lack of provisions.
Despite this fact, they chose to initiate combat. The basic reason is so simple and obvious that it seems to not be paid much attention.
In April of 1865 seven states had seceded. There were eight more slave states in the upper south and border. Lincoln and many in the north believed, rightly or wrongly, that a long stalemate would lead to a rebound of unionist sentiment.
It seems Confederate leaders agreed. They chose to start the fighting, gambling most or all of the "states on the fence" would join them when forced to choose a side.
Virginia and other upper south states reacted with calls for secession as soon as news of the firing on Sumter arrived. Though they used it as their claimed reason, this reaction occurred before Lincoln's call for troops to repress insurrection.
Had all eight unseceded slave state supported the Union, the war would have been short and one-sided. Had all joined the CSA, it would have won, as Lincoln himself said.
In fact, they split 4 and 4, which ensured a long, bloody war.
I am not arguing that the firing at Fort Sumnter was right.
In fact, I personally believe that there were better ways to handle the situation without having to resort to fighting ( e.g., a diplomatic protest for instance at the presence of Northern soldiers in a state that considers itself independent. Negotiations should have been exhausted, I believe ).
The North didn’t help either by resorting to invasion when nobody got killed at Fort Sumnter.
So, both sides were belligerent and this war really was not necessary.
I also believe that slavery would have died without the civil war ( most countries that had slaves, north and south of the equator eventually abolished them without having to kill one another ).
My argument is that the original understanding of the union was that the states had the RIGHT to secede for reasons they deem necessary if their independence or well being was not being protected by being members of the union.
I still believe this to be the correct understanding of the original intent of those who agreed to join the United States.