Very interesting post and good points. Sustainability is indeed a complex topic. To a great degree I beleive sustainability is a method of managing, that begins with the individual. The ultimate goal is to sustain life on hearth and to take actions that will give future generations opportunities to meet their own needs.
It is also recognizing that there are environmental, economic and social aspects to sustainability. And there those 3 broad topics are connected with local, regional, national and international aspects of each topic. For example, a golf course my conduct itself in an environmentally appropriate manner from a local point of view, but at the same time purchase and use products that could imped environmental and social impacts in their manufacturing and distribution processes that would not be so good. This gets to the old saying, "Think global, act local." But in the case of sustainability the goal is to "Think global and act local and global."
I believe the place to start from a golf course point of view is to focus on the soil. I believe that healthy and biologically diverse soils are the foundation for healthy ecosystems. We are litterally flushing our top soil down our river systems and causing deadzones in our oceans. As a result many are using large quantities of chemical products and water in an effort to keep vegetation growing and green. Much of these chemical products actually make the soil less healthy and therefore increase the need to purchase and use more of the chemical products. It is an unsustainable circle.