In the wake of the Fourth of July weekend, I watched parts of the movie, Gettysburg, and re-read some of Shelby Foote. The North had plenty of manufacturing capacity. Putting firepower in the hands of the soldiers repeatedly proved to be very effective. For example, Northern cavalry armed with Spencer repeating rifles out-gunned Southern cavalry. It would seem that Federal soldiers, if armed with a Colt Army Model 1860 (.44 caliber, 900 fps) would have been very effective at 50 yards.
The Springfield rifled musket was $20 a copy and Colt originally sold the revolver for $20 also, although the cost was later dropped to $14.75. The Remington 1858 was in the same price range.
Was it only cost that precluded arming all soldiers with a revolver?
Was a class thing, that only certain ranks and troops could have a revolver?
Was a logistics issue, providing ammo for two weapons instead of one?
Was there ever a move look at the balance of a soldier's lethality and survivability?
While the US were certainly way more industrialised than the south, and the bigger population, economy and industry of the north eventually decided the war, the US lacked the ability to quickly expand its production facilities (this was the case for all industrial powers at the time, and would be the case for both US and European nations' industries in ww1 as well) to equip and supply the massive amount of men that volunteered (and later were drafted).
US production of rifles during the war came to roughly 1 500 000 weapons, with imports of roughly 1,2 million weapons, including 900 000 British Enfield rifles and 227 000 Austrian Lorenz rifles.
Roughly 127 000 Colt revolvers were delivered to the US army before the end of the Civil War. And they wanted more for the cavalry and the navy, but Colt was unable to deliver more.
As you can see, there were not enough revolvers to equip all the men (at most about 10%), and getting each man a rifle so he can fire at range with his comrades in arms was far more important than getting revolver firepower out there.
Remember that military thinking at this time considered rate of fire a bit secondary for infantry - with lines of men firing blackpowder weapons and artillery fire adding to that, the enemy and your own formation quickly became enshrouded in gunpowder smoke.
Cavalry on the other hand was expected to move around a lot more, and were also more often equipped with quick- breach-loaded or even repeating carbines and revolvers.