Presumably then at the end of each Grand Cycle a new group of humans on this planet achieve sufficient awareness to make the leap to 4D. Thereby the existing pool of humans being re-incarnated grows ever smaller. I wonder if 4D STS are just hanging on to the remainder as long as possible so that they have an agreeable amount of energy and "food" for as long as possible. Even they would have to know that all good things come to an end eventually...or not. Perhaps they are into self-deception in a big way.