I guess I'll believe it when I see that the powers that be have found a way to make more money by using less energy and being sustainable. But I seriously doubt that this society will find any truly sustainable path given that greed is so ingrained in people's minds.
To be truly sustainable, according to various online carrying capacity calculators, the average American would need live in a space about 550 sq. ft. in size and mostly walk, ride a bike, or take public transit everywhere, and practically never fly in an airplane. In addition, this sustainable American would need to be vegan, use one LED lightbulb, and re-cycle ALL household and human wastes. How many Americans do you know currently live like this or who would be willing to live like this in the future? Almost or practically known except the many homeless, landless, or the free spirits that are on the streets, right?