I am certainly not smart enough to answer the questions that have been
raised, and am not sure I even know where to start looking for the answers.
But, your suggestions of starting by looking at actual cases -- farms,
communities, cities, societies, etc. - and trying to understand what makes
some at least appear to be more sustainable than others would seem to be a
good place to start. The thing of which I am most sure is that we have to
begin observing, asking questions, formulating hypotheses, and drawing
conclusions using a fundamentally different paradigm of science - holism
rather than reductionism, as suggested in Bawden's sabbatical paper. In a
sense, we have to start over again. We all have something of value to
contribute to this process -- we are all dimensions of the whole we are
trying to understand -- but we need to admit our mutual ignorance as we
search together for understanding.
One parting thought on this subject, we need to think from OUTSIDE the box.