In order for something to be sustainable it has to be profitable. The idea that we put "sustainability" ahead of profits is stupid, or ill informed, if you prefer the gentler way of saying it. These ranches that are going on third and fourth generation of operation are the epitome of sustainability. They are demonstrating their sustainability every single day. They don't need mission statements or cute little catch phrases like "buy local" to keep them in business and do what is best for the environment. If what they were doing wasn't best for the natural environment they would have all ready gone out of business, thus ending the "sustainability". It always amuses me when the backyard farmers want to come preach to the people that are feeding the rest of the world that we ought to be marketing locally. The fact of the matter is our diets would stink and people would starve to death if we all tried to follow that model. Our diet is healthier and more varied because the average citizen doesn't buy locally.
The fact of the matter is that the food supply we have today is what it is because it has been proven to be the most sustainable. When it ceases to be sustainable something else will replace it. But I can guarantee with one hundred percent certainty that it will not be the model that is being advocated here. We tried that model 100+ years ago. We quit doing it because it was a crappy way to live and eat.
Now I am going to go put my soapbox away and go back to lurking.