That excellent meal you enjoyed and reflect on over and over, yet regardless of your attempts, you can never replicate it. You check the composition of ingredients, the directions, and the prep and rest times. What could be at fault?
We forget that not all things are equal, and the most basic of all is the ingredients. No matter how good the recipe or the chef, it will only ever be as good as the ingredients used. Not all tomatoes are equal, and nor is everything else.
We can appreciate this regarding food, yet do we accept that this applies to all we do? Your team can only function at the level of the worst people who are a part. Your systems and process will only be as good at executing on the worst day.
It is not your vision or the implementation plan that is the foundational issue but what you are starting with. There are no givens, but accept that the outcome will only be as good as the worst ingredient.