The phenomenon you're describing is largely specific to those obnoxious people. You see many more people "thinking about what they are eating" because you run in circles where people talk about it. I would argue that the notion that it's spreading to the parts of the country that need to start caring more about their diets is demonstrably false and largely impossible because the "farm to table" thing (in its current form, at least) is far more expensive than those people can afford. The farm-to-table zeitgeist demands much more than a backyard garden. And in any event, for the poor, a garden is not the beginning of some teleological progression toward a healthy "food cycle (insert foodie buzzword here)" or something. It's easy to forget that the ultimate reason poor people tend to eat less healthfully is that healthful food is more expensive; mass produced crap is always going to be cheaper.

I don't think it's an impossible cycle to break, but as with most things that are common in our moderately wealthy circles, they have virtually no resemblance to or effect on what happens in urban ghettos and rural America. You might as well be sticking your head in the sand if you think that only eating at restaurants with locally sourced ingredients and growing tomatoes on your fire escape has anything to do with what Joe Schmo in rural Kansas is eating for lunch. Indeed, fast food continues to be a growing industry in spite of the fact that increasing numbers of affluent people now refuse to eat it.