For some of them I would say that they barely had any strategy to reduce that risk, and just had people whose sole job it was to constantly try and identify new

For some of them I would say that they barely had any strategy to reduce that risk, and just had people whose sole job it was to constantly try and identify new products, and then they just accepted that they had better or worse months of that working. The merchants where it was more stable had generally less of those products, and had a bigger existing offline business. Through their offline business they had bigger volume on those products and could cut a better deal with the supplier than Amazon, and through that offer them at a lower price[0]. I would guess though that that's also only a very temporary position they can hold, as Amazon should be able to beat them in warehouse logistics and demand forecasting. [0]: As a silver-lining Amazon is pretty fair that if you underbid them even if they have the item in stock themselves, you will still make the sale "by default".