In fact, half of US cotton exported directly not from New York, but from New Orleans. This is true, but you are leaving out the fact that New York was the controlling city of all that export traffic from New Orleans. As a matter of fact, I first learned that tidbit in a link you provided years ago.
New York controlled the cotton trade almost completely, and they did so as a consequence of controlling virtually all the shipping in the United States.
75% of imports through New York seems about right, where goods were off-loaded, warehoused, then eventually sold & shipped (via railroad & steamship) throughout the USA -- North, South, East & West.
Lot of money involved. Would be a terrible shame if that traffic and business all moved to New Orleans, Mobile, and Charleston. Shame for wealthy and powerful New York business owners that is.
DiogenesLamp:
"New York controlled the cotton trade almost completely, and they did so as a consequence of controlling virtually all the shipping in the United States." "New York" is a place, not a person, and people who may or may not have lived in New York built, owned & operated many thousands of US merchant ships.
By the way, the overall percent of US exports & imports carried in US owned ships reached 93% in 1826, fell to 65% by 1861 and to just 28% by 1865.
The US merchant fleet never fully recovered afterwards.
So all those powerful New Yorkers, who you claim "ruled the waves", in fact were rapidly phasing out of international shipping business.
DiogenesLamp: "Lot of money involved.
Would be a terrible shame if that traffic and business all moved to New Orleans, Mobile, and Charleston.
Shame for wealthy and powerful New York business owners that is."
People who built & operated warehouses in New York would be just as happy to build & operate them somewhere else too, if that made economic sense.
One place it did make sense was New Orleans, which was consequently booming. 