[qchris]

I think that there's some degree of "you can't get to the moon by climbing taller trees" happening here. There are methods that can be promising for gardens, and even smaller-scale farms (less than triple-digit acres, say) that don't feasibly scale up to what amounts to continental-scale farming like you see in much of North America. It doesn't mean that those approaches don't have value, just that at some point the scale of the problem space changes things pretty fundamentally.