The book "not the end of the world" by Hanna Ritchie makes a neat point that humans have never lived in what we would call a sustainable way, but it's possible for this generation to be the first one that does.
How is that possible? At some point there were a small amount of humans and they probably were not able to consume resources faster than nature can replenish them
Either there is a first sustainable generation, or one day there will be a last unsustainable generation.