Once, in 1842, and it had nothing to do with wool.
Brown's second business failure, in 1848, was wool, but the losses were absorbed by Brown's business partner, one Col. Simon Perkins, of Akron Ohio.
DiogenesLamp: "Apparently he figured that being the Antifa lacky for Wealthy interests in the North East was more profitable.
There's no evidence Brown's anti-slavery activities had anything to do with a profit motive.
DiogenesLamp: "His efforts to organize the Massachusetts wool merchants just never went anywhere."
Right.
Two of Brown's "secret six" were relatively wealthy.
Neither had anything to do with wool.
DiogenesLamp "And yes, cotton and wool do directly compete.
The vast majority of people wanted cotton, because it was cooler and less irritating than wool."
"Cooler" is not necessarily desirable in cold Northern winters.
Nor is wool necessarily irritating -- i.e., flannel, long used for "Union suits" (before there were "long johns" there were flannel "Union suits").
Sure, cotton is cheaper than wool, but John Brown's problem was not cotton, it was much cheaper types of wool than he produced.
Brown tried to upgrade his customers and wool producers to a higher (so more expensive) type of wool, and they just weren't buying.
That's what caused his business to fail, not cotton.
DiogenesLamp: "If cotton wasn't available, the usage of wool would have increased dramatically, because back in those days, they didn't have very much to chose from."
No, if cotton wasn't available from Southern US producers, then US & European mills would buy it elsewhere, i.e., Egypt or India.
That's what happened.