Large scale conventional farming is akin to mining. I guess it's always the little guy who gets enlightened first. There are a lot of small farms practicing sustainable agriculture. It feels like it's taking way too long to persuade conventional farmers to clean up their act (and to persuade consumers to make better food choices), but the number of acres involved in sustainable farming has grown quite a bit in the past decade. Human nature being what it is, I don't know if we'll ever get the majority of people to behave responsibly over the long-term. But, the current trends do look promising.
http://en.wikipedia.org/wiki/Organic_farming
http://en.wikipedia.org/wiki/Sustainable_agriculture