Answer: She failed to research on the general demand for cupcakes.
Explanation:
Vicki did a good thing checking what types of cupcakes were in demand and then planning her menu accordingly but she should have checked for cupcakes demand in general. From the looks of this, it would seem that cupcakes were just not as popular as they used to be so regardless of the type of cupcakes sold, Vicki will not see a huge demand.
This is like oil companies discovering a way to make gasoline cleaner but it still wouldn't sell as much because less people are using gasoline in general.
