To become a pure Consciousness Entity, casting aside one's frail flesh is a necessary path for everyone.
Long ago, during the dark ages, the Church began to greatly propagate the importance of asceticism. This life filled with suffering, apart from satisfying some "Deities'" harmful predilections, was also to let believers gradually adapt to the process of spiritual and physical dissociation.
Even at the height of Spiritual Energy civilization, only a select few could complete the Ceremony.
They were either the cream of the crop among Ascetics who, after prolonged starvation and torment, had elevated their spirits; or they were individuals of unique talent who had also received the favor of a "Deity".
Yet a situation like the universal transformation into Consciousness Entities had never appeared in history.
For the majority of life in this world, both soul and spirit need to rely on the body to exist—forcibly separating the two would lead to their rapid dissolution.