I tend to agree with you, but we also know that it can be done, or we wouldn't be here typing on the internet while our arteries are hardening from the abundance of food available to us. We got from there to here, and we have the knowledge we picked up along the way to help us.

What we need to do to prepare for a breakdown of our society is to establish communities of people who are relatively close to us and have skills we will be needing that go beyond just growing food. We will need carpenters, metal workers, mechanics, medical personnel, and farmers, and, of course, land.

Archeologists determine if a society was civilized by evidence of broken bones that healed before the person died. That indicates that a "society" existed that was able to feed the person, as well as themselves, while also tending to the injured person to enable them to survive and pass down their knowledge and skills. The first thing most preppers are willing to abandon is likely the most important part of survival, society.