People tend to make that argument a lot when someone analyzes design, and it betrays an ignorance of the craft.

When you design something complex, your eyes and mind have to examine and make decisions on every detail. Even if the decisions took much less time than someone's later analysis, it's still a decision and there was still a significant amount of conscious or unconscious thought surrounding it.

Notice I said 'unconscious' thought? In this case, analysis is even more important, to help drive out a discussion on elements that nobody's really had yet. You might balk at calling someone whose obviously just 'threw something together' a genius, but the hand and eye and mind that threw something together like that managed to do something that thousands of others try and fail.