I think that the metaphor leaks badly. Finding market fit is like deciding on the general shape of the staircase. Execution of whatever design still needs the stairway to be strong and reliable all the same.

Writing code is a much more precise activity that cutting wood. Using "cheats" can get you somewhere, but due to the precise nature of the machine logic, the contraption is guaranteed to bend and break where it does not precisely fit, and shaving off the offending 1/8" is usually not easy, even if possible.