My shot for your post:
As friendly shaman explained it to me once-
- different starting level is some kind of the POOf for the reincarnation .
Spiritual path is quite long, each of us has different tasks to fill during the present possession of the body.
Next,
Possession of the material body, in earthly sense, brings additional border/s/ - our senses are tailored for "material word",
so ,
for ex.:
You unable to see atoms, or to sens, that in the fact "atom" isn`t something what you can touch, it is vibration aka -energy.
However,
we are able to learn, and use imagination

but
this is spiritual path, and travels here is much longer than one life span process .
During our long way we learn lot of different things with our own peace, some of them has to be polish longer than ones life,
we are reborn with knowledge, however hidden to the degree of personal achievement.
This is the main reason , that particularly gifted individuals are between us...