The Fallacy of Customer Development

I agree that the idea that "customers hold all the answers" is flawed, but that's not what customer development is. A better phrase would be "no answers are found inside the building". You can't just ask people what they need and build it, that's not customer development. Customer development is about finding a problem worth solving and that people are willing to pay for. You need to understand the problem thoroughly, and that requires you to get out of the building and talk to lots of people. If the solution was obvious, and the people you talked to told you what to build, then you wouldn't have much of a business, because the problem would be easy to solve (and someone would have solved it, or they'd do it in house).

Customers don't hold all the answers, but they can point you to the right solution. You still need to come up with an optimal solution. Once you reach product-market fit, then you can work on optimizing customer acquisition. Before product-market fit, you don't know what your product really is or who your customers really are. Any time spent optimizing that is time that could be better spent finding the actual problem and getting to product-market fit. At best you risk wasting time, at worst you risk following the wrong path because you've invested so much time optimizing it, which would make pivoting to the "right" product/market much more difficult.