Sustainability can't be like some sort of a moral sacrifice or political dilemma or a philanthropical cause. It has to be a design challenge.
A shoe is not only a design, but it's a part of your body language, the way you walk. The way you're going to move is quite dictated by your shoes.
The universe we observe has precisely the properties we should expect if there is, at bottom, no design, no purpose, no evil, no good, nothing but blind, pitiless indifference.