When an article like this uses the term "smart people", I'm always a bit confused if they mean actually smart people, or not-that-smart-people-who-think-highly-of-themselves. Because there's a lot more people in the latter category, and in my view they are the ones building unnecessary complexity into codebases.

To clarify, when I say "not-that-smart-people", I don't mean "stupid people". You need to be beyond some basic level of intelligence in order to have the capability to overcomplicate a codebase. For lack of a better metric, consider IQ. If your IQ is below 80, you are not going to work day-to-day overcomplicating a codebase. You need to be slightly above average intelligence (not stupid, but also "not-that-smart") to find yourself in that position.

It takes intelligence to see where to make a change though.

If you make a change at the wrong place, you add more complexity than if you put the change in the right place. You often see the same thing with junior developers, in that case due to a limited mental model of the code. You give them a task that from a senior developer would result in a 2 line diff and they come back changing 45 lines.