In that sense most things are simple. Though it's also simple to over simplify. Since often simplicity arises out of the accumulation of expert analysis rather than being obvious from the get go. Which I think is just as important as what you say:
Simple means not complex, means not composed of even simpler parts. A twelve step plan is literally a list of simpler parts, making it not simple. Most things are complex, since there are so many ways to combine simples. It is an ironic title.
I disagree. Most things are complex, yet most things are also simple.
Don't forget that words are overloaded so they only mean things in context. Words are both simple and complex because of this.
As an example: the rules to the game of life are simple. The outcomes are complex. The rules cannot even be decomposed further, making them first principles of that universe.
> means not composed of even simpler parts
These would really be "first principles". Which is a form of simplicity. Being the simplest something can be, yet that sentence itself conveys that "simple" relies on context and in a continuum.
This relationship of "simple yet complex" is quite common. We could say the same thing about chaotic functions like the double pendulum. It is both simple and complex.
