An outside expert's understanding of somebody else's problem is bounded, because they do not have to live with the design after they leave.

Your understanding of somebody else's problem is bounded because you're not in the middle of it. You don't have the same skin in the game. If you're not semiconductor test engineer, you don't have as much skin in the game as somebody who is because they're going to have to be using this interface for a long time after you're gone.