Sustainability doesn’t pertain only to the environment. The root of the word itself means to sustain. Businesses need to sustain themselves to continue their operations and grow. People need to eat in order to sustain themselves and their physical health. The energy we use needs to be sustained by its source. The leftover food you’ve put into the fridge needs to be sustained by its cold temperatures, and so on.
Sustainability keeps the world running, and greed is what kills it.