@Beyond Everything how do you know there is no Soul and no reincarnation? I can quickly give you a very powerful counterargument to your thesis-what constitutes the Soul and what reincarnates through the lifetimes is essentially the same thing-
a free will! There is only one will in many bodies and these different bodies are only but its different stages of development. That is how the Soul and its evolution are best explained-if there was no Soul and we were only "an energy complex" how do you explain karma and Soul evolution? How does your model fits in the Path of consciousness through the material world? What creates, and erases, the new consciousnesses according to your model and where does their karma goes? The one will in many bodies bound by the laws of cause and effect-which manifest themselves as karma is
the best explanation for what we observe and any, and all, candidates for better explanations need to handle those questions first-how do you reconcile a very limited existence of consciousness bound to a body with the karma it generates, and how does the evident existence of personalities on different levels of their spiritual development occurs without a reincarnation? Please, answer those questions if you still think your explanation is the best one.
As far as the topic is concerned-I have my personal believes about the subject I wish to share here-I think the oldest Souls ultimately always encounter The Choice-the greatest choice any soul stumbles upon and the one which ultimately paves the way for its final destination. This is the choice as to whether to merge with the Source, or become a Source themselves. This is what the final evolution of the Soul manifests into and it's essentially the mechanism for the removal of really really old Souls from this form of existence. If the Soul chooses to merge with the Source its free will disappears into its own and then its existence as an independent entity ceases. In other terms the Soul is dead to the world but it had managed to achieve the highest level of bliss and maturity accessible to it in this Universe and thus it is very happy that it finally doesn't need to do anything else but submit to the will of the Creator. On the other hand if the Soul wishes to become a Creator itself than it must take up the mantle of the heaviest mission available to Souls in this Universe-how to choose a plan for another Universe itself and become the Creator in its own right. And the existence of these two options for very old souls is the reason why there are no too old Souls which would tend to stick around here, in the "lower" dimensions. The oldest ones have either chosen to merge or to become Creators and this is where they have gone while leaving us with the "kindergarten" of Souls, so to speak.