Karen, I believe a lot of folks have studies this, and the work of Steve Blank and the Lean Principles movement has won over most. That methodology is all about the Customer Discovery journey. Founders must search for, and validate, their Customer Hypothesis before building a of of their solution. What's been proven si that the founders assumptions always are not 100% correct, and proper interviewing leads to identification of real pain that customers are looking for and will pay for. The successful entrepreneurs are able to make these pivots and adapt to what they hear through these interviews.