I think of the quote as more of a cautionary tale than a logical argument.
From my personal experience, I have learned that those truly clever and amazing pieces of code that I and others have written always seem to take an extraordinary amount of brain-power to understand and debug later.
I've also found the quote as useful for making entry-level programmers reconsider their latest masterpiece. Thinking about what it will take to debug a complex system can be a useful antidote to an overly complex design.