This certainly has been the case that with awakening, insight - direct knowledge - into Reality is possible, while the dark side remains.

But there are hints in the ancient Vedas and in other indigenous texts that this thousand-years cycle of awakening while leaving one's nature (mind/emotions/life/body) unchanged may be coming to an end.

Sri Aurobindo and Mirra Alfassa spent decades exploring another possibility - that over the case of lifetimes, it may be possible for a radical transformation of one's nature to occur.