Hi Amjad, excellent points.

• You’re dead on about fulfillment and import costs. I responded to an earlier comment admitting that I forgot to account for fulfillment costs. There’s the possibility that because they were college students, they got external help from friends, family, fraternity members, etc. They also fulfilled all orders over the period of a few months because they were not expecting this level of demand.
• As for import costs, in my experience they tend to run a couple thousand dollars thanks to third party services that exist to help minimize costs. In the context of six figures, that’s relatively small, but you’re right — definitely not insignificant.
• Completely agree regarding quality control. I emphasized in step 2 of the article that this component is critical. Anyone who does this should spend time ordering multiple products from their supplier.

Bottom line: the framework is straightforward, but the execution is hard.