The death birth cycle is a natural and powerful rhythm of rejuvenation. The positive, or symbolically masculine, explosion into form - and then the negative, or symbolically feminine, withdrawal into formlessness. The introduction of frequent blank slate, as Original Poster said.

This is not just a rhythm of the body, it is a rhythm of the inner self as well. Any creative thought comes first from that initial explosion, fed into the mind from subconscious depths. The mind gives it structure and applies it in concrete ways to physical life. However if there is no corresponding withdrawal back into formless or unity, an empty structure is left over to be tossed around endlessly by the mind. All religions stem from that initial burst of creativity, yet they lack the feminine death rejuvenation so the result is dogma.

In terms of the lifespan of the physical body, it is my opinion that it could be increased substantially as long as individuals are able to introduce that blank slate. True immortality would result, eventually, in stagnation though, and would be clung to more out of fear of death than love of life.

Furthermore, the body is a projection of the inner mind. Frequent dissolutions into unity rejuvenate the body as much as the mind, and lack thereof cause stress and increase aging.