These two should be true for an incubator/accelerator or group of advisors/mentors/investors.
At the end of the day, the founders build the company, not anyone else. "Outsiders" (those who don't actually work in the company) should offer guidance and frameworks, but never a definitive solution to the problem you're having, that's for the founders to figure out and decide for themselves.
1. But you still need to figure out things by yourself: YC will never tell you what people want
2. If there is one thing that is true about YC partners, it’s that you can’t expect them to do the work for you.