A perfect plan that does not survive contact with real customers wastes cycles and gives an illusion of knowledge that hides how things work.

you come up with the perfect plan based on that, that doesn't survive the first touch with reality, with actual potential customers who are trying to do things. Like, you just waste a lot of cycles and it gives this like illusion of knowledge, the feeling of knowledge, the feeling of having a plan, and prevents you from seeing how things actually work.