That's a very good question. I am wondering that myself. I would say that not remembering past lives would be because mans brain is not yet advanced enough to access these memories.
Man only uses around 10 percent of his cerebral potential. If such memories in fact existed they would be deep within a mans bran. On the edge of his DNA to give room for his new memories.
Perhaps junk dna is just memories and skills from past lives we cannot yet access. The reason why our brain needs to be advanced enough to access these memories is probably because if we accessed these memories while using only 10% of our potential we would probably go insane because we would not know who we are and we could not make sense of the knowledge that we posses from the past lives.
Traditional reincarnation is the return to earth as a different entity after death. This allows you to think of other beings as if you are remembering being one of them. The future entity you become relies upon the life you live in the present.
It is an Indian form of immortality. It does not however explain the increase of population in any logical way because the population of humans and animals would stay the same and everybody would have to return to the story of Noah in Genesis!
I cant really gove you an answer,but what I can give you is a way to a solution, that is you have to find the anglde that you relate to or peaks your interest. A good paper is one that people get drawn into because it reaches them ln some way.As for me WW11 to me, I think of the holocaust and the effect it had on the survivors, their families and those who stood by and did nothing until it was too late.