I somewhat disagree with the way he connects simplicity and cleverness.
I once had to explain the behavior of a particular subsystem. It was governed by a bunch of simple rules, but their combination created a complex behavior. This was similar to social insect colonies, where components (eg. ants) are driven by relatively simple rules, but the whole system exhibits remarkable "emergent behavior".
What takes cleverness is to anticipate, predict, understand,explain the global complex behavior from the simple rules. If someone can predict what comes out from cellular automatons like in the game of life, I am amazed. Simple is not easy (no, sorry Rich, following your simple advice is not that easy either). Simple is not always easy to understand, even less so easy to do. That's why complexity tends to accumulate.
At the risk of being wronged, I would say that being comfortable with complexity is a form laziness. I belong to the messy type of person. I believe I am that way because I can rely on a good long term memory: because of that, I can yield to laziness and not put away things where they belong when I should. Being able to handle complexity is a great quality, but not being discomforted by complexity is like not being ashamed by your messy home.
When you make the effort to really simplify, under the favorable circumstances (like in hobby projects, where you can afford to move goalposts a bit), you can make complexity collapse - not by its own weight, for once. I understand that the author emphasis teamwork and communication so he gives this kind of John Wood's "Always code as if the guy who ends up maintaining your code will be a violent psychopath who knows where you live" justification for fighting complexity, but preventing complexity from collapsing by its own weight, crushing a product in the process, is to me on equal grounds.