I think that economic sustainability applies to so much more than just microeconomics. Economic sustainability applies to the state of natural and design systems. At its heart, economics is the study of making decisions under scarcity. Until this point and likely into the near future, economic decisions were based on the most efficient use of resources relative to the designed environment, even though these resources come from the natural environment. There has been this train of thought that the planets natural systems are endlessly elastic, able to recover and impervious to the pressures of one species. The assumption is that we will design our systems and natural systems will adapt, but what we have found out is that the natural systems do not adapt in the manner that we had planned.
Sustainable economic development on the other hand is decision making and problem solving based on a desired outcome rather than what is the most profitable momentary outcome. In essence it turns the natural and design sciences on its ear, by shifting the way that problems are approached. Innovation occurs out of a need to reach a desirable future outcome, rather than exploiting what is available in the fastest manner possible. I would go a little deeper into this, but this is only a comment section, so I wanted to give people something to think about.