Slavery is only a reason for the war as it was the reason for the initial secession of the first six states (SC, GA, FL, AL, MS, LA). It is worth noting though that the vote for secession in even a number of these Deep South states were extremely close (see Georgia and Alabama in particular), and of course the vote failed outright in the Upper South. It was only after Lincoln decided to invade the South that the 'moderates' came around to secession in order to help defend their fellow southern states.
Look at a map of Tennessee in it's vote on secession for a good example. In February it failed, but after Lincoln called up troops, it passed with a pretty heavy vote (except in East Tennessee).
Also, it is near impossible to speculate on the economy of a victorious Confederacy for obvious reasons.
It's rather unfortunate that the state of East Tennessee (State of Franklin?) wasn't created during/after the war a la West Virginia. The butterflies/differences would have been fascinating.
Also lol at the Neo-Confederates in this thread.
