Yeah it could be a cyclic event that we have no control over. Even the great brains can't prove it either way.
Thing is mankind is a virus on this earth...just too many of us and we're breeding at an alarming rate. Mother nature will find a way to sort that out for us anyway.
To give an idea of the expotential population explosion it's a fact that over half of the people that ever existed (Adam/Eve or Darwins version)are alive today.
The maths of that sort of shoots down those who think they've been Pharohs, Samurais and Einstein in previous lives