It’s important to have a great vision: Computer on every desk -Steve Jobs, or building the tallest building or, sending a man on moon etc.
Big picture or great vision is just a fuel, just a motivator, but when the fuel goes down in the engine, there has to be precise processing of it, every detail counts, every optimization matters, and the end result is dependant on the quality of execution.
The engine or the process is the craft, talent and skill of the people working on the project.
These people have to be put together by the visionary, but the vision can only be made.reality by these amazing skilled workers.