My theory is this:
There was God. He had a son, named Michael. Michael then went on to have a whole big bunch of sons, millions of them in fact, and also went on to create human children.
Now, one of Michael's children, Lucifer, and many of his brothers took issue with Michael his father (and indirectly his grandfather God) and decided since he couldn't take on his father and grandfather, he started playing with the humans and manged to lead them off the favored path. As a result, the first two humans created by Michael then 'died' . Not that death was unfamiliar to the angels, they had been watching animals and plants live and die for who knows how long.
Now there had been a legal principle involved here, that if Adam and Eve went off the beaten path they would die. They went on to have children, they died too. That was their sentence for disobedience.
And Lucifer? Death also.
Michael had sentenced the human pair to death, but he did not kill them. The first passive euthanasia if you will. They died on their own. It is to be assumed that Lucifer someday will do the same. In any case, neither God nor Michael have any desire to kill Lucifer and his brothers, and so they let them live out their natural life span, passive euthanasia again.
One cannot blame someone for not wanting to directly kill their own child/grandchild. Maybe Lucifer was given a choice, slow death or fast death and the slow way was his choice. In any case, like the humans and animals, Lucifer and his unfaithful brothers age the same way as humans, growing gradually weaker and feebler as the reach the end of their life span.
My support for this reasoning? The fact that the world is a better place today than ever before. The two world wars that occurred in the world was a last act of dying creatures, expending what was left of their energy to try and take out the world with them when they departed.
It may also be the reason jesus waited so long before coming to earth. Thousands of years had gone by, and Lucifer's followers all are old and weak and were not able to kill the baby Jesus. A few thousand years previous, the war between the two factions of heavenly siblings to protect/kill the fragile human child might have ripped apart the planet. By waiting untill Lucifer had weakened, whatever fight Satan put up over the baby went unnoticed by all but those in the near vicinity.
Even a mere 30 years later, Satan could not directly take up issue with Jesus. He had to try and bribe and bully Jesus into diverting from his path, he couyld not begin to muster up enough force to try and 'take' the human.
The promise of God and his Son Jesus, is that in return for all the damage the rampaging dying Lucifer was doing, humans the offspring of Adam and Eve would be restored everything they had lost, including their lives and teh pristine planet and everything else.
one has to wonder why God/Michael could not wall earth off from Lucifer and his rampaging dying army. Could not or would not.
For this I have no answer.
