The problem is that you already have a clear picture of the complete puzzle and you just try to force various pieces together even if they don't fit only to arrive at that preconceived vision. You take it too seriously. I for one think that the image of horny immortal fertile procreating humans is hilarious. Just consider all the consequences :D

Anyway, if you are unwilling to discard ideas that don't add up, you may enjoy your speculations all you want but they will always remain in the realm of fruitless pastime.