This closing paragraph is excellent.
While I do wonder if the author's progress along these wouldn't have been accelerated if more of this evolution took place before the first line of code, the overall message here is very true and very well put.
When I made this realization for myself, it was a major turning point in the quality, speed, maintainability, and usability of the code I produce, especially when I can successfully define the final code structure to directly reflect this progressive refinement from intent to implementation.