You are referring to things like "banking", "Insurance", "warehousing", and such.
Were these things not profitable? If so, couldn't the Southerners have done them for themselves at profit, especially when they would be getting an additional 40% of the cotton profits to provide capitalization?
They would have the added benefit of not having to do business with people calling them the worst scum on earth, as Liberals do to all of us nowadays.
What was stopping them from starting their own shipping companies, banks, insurance companies, warehouses and such, beyond what they already had in 1861?
But of course they didn't.
Instead they did business with their political allies, economic partners and social friends, Northern Democrats.
Northern Democrats had no problem with slavery and together with Southern Democrats they ruled in Washington, DC, almost continuously from 1800 until secession in 1861.