"just in time for the San Francisco International Gift Show...I soon began sales calls on buyers ranging from novelty shops and porno stores to gay rights groups and Planned Parenthood clinics...People began buying my key chains. Small gift shops in small towns bought dozens and dozens and regularly reordered"
His failure seems mostly economic: his financial projections didn't include all the overhead involved in importing the keychains, getting them ready for sale, and shipping them out to retailers. And much of that was because he didn't know all those things were required.
He would've been saved by researching the supply chain better, not the market.