1. Quite often, the entrepreneur has no idea how to market/sell the product without offending anyone. Even though they may be a great inventor, importer, writer, etc., they don't know how to create a benefit-oriented sales message because they are not in touch with their customers.
2. They grossly overestimate the demand and importance of their product in the marketplace. Many people think they have a winner, something everyone in the world needs. Generally, products appealing to everyone appeal to no one.
3. The biggest problem is the product is not positioned or even suited to the Internet or to online marketing. It may sell very successfully in specialty retail stores, or via direct-mail, however, the online market place isn't interested enough to actually pull out their money and purchase. Or worse, the marketplace is used to doing business a different way and can't see themselves ever buying "X" on the Internet. Examples: cars, jewelry, boats, health products etc. However, we believe this point is constantly becoming more of an exception as more people go online shopping, but only you can know the type of customer demographics you have in your hands now, and whether your site is playing an active role in selling and delivering your products via dropship.
Here the classic verse that has been around since it was uttered by some well-known guru applies: "Pick your market before you pick your product. Then, you can be sure you are selecting a customer group you want to do business with, one with money, and passions you can appeal to or problems you can solve."