The whole "unsustainable" part is what gets me. Why is "growth" so important that we must do it to a point where it becomes unsustainable and risks literally a

The whole "unsustainable" part is what gets me. Why is "growth" so important that we must do it to a point where it becomes unsustainable and risks literally all life everywhere on Earth becoming extinct (or at least knocked back to pre-stone age levels)?