I have to say that your first statement seems totally ridiculous...do you really think that homo sapiens
is homo economicus?? People are not rational optimizers, they're mammals. I'm sure I'm being a bit uncharitable to your claim here but your comment makes you sound like you actually are the 'older, wiser' economist in that old joke: "Two economists, one young and one old, are walking to lunch. The young economist looks down and sees a $20 bill on the street and says, 'Hey, look a twenty-dollar bill!' Without even looking, his older and wiser colleague replies, 'Nonsense. If there had been a twenty-dollar lying on the street, someone would have already picked it up by now.'"
As to your second paragraph...have you considered the possibility that you, specifically, didn't do a good job of cooking for yourself and that the fact that you failed to cook this way could be, well, your failure (to plan or execute or whatever), rather than a global failure of the idea "cook for yourself and use fresh produce"?
As for farm shares, many/most CSAs deliver, either to the home or to a central location in town (often a local co-op). So it is, in fact just one delivery truck driving down the highway.
And to your final paragraph, I simply say that that is an utter failure of imagination. At the moment, it's absolutely true that participating in this kind of eating & cooking demands some flexibility of schedule. Mostly, wealthier people are the ones who eat this way. Now, why is that the case? Well, our entire food production and distribution system is built around a different model. Deviating from that model, given the current state of the system, is expensive. That doesn't mean that people with the power and resources to do so shouldn't actively work towards changing the system into somethign more sustainable and accessible for all. In fact, in NYC there is an incredible farmer's market (called "greenmarket"), which runs in several poor neighborhoods and accepts food stamps, and it's life-changing for many people. I think that if you spoke to a few of the people who shop there, you'd never be as offhandedly dismissive of "eat fresh produce & cook for yourself" as you are here.