Suppose letting humanity do whatever it wants for a more or less fixed period of time before God puts and end to it is really God's plan?

Suppose the Devil, the first rebel, is allowed to corrupt the minds of all who will let him, such as Adam, and that humanity is given a relatively long time to learn that man cannot successfully direct himself before God steps in and removes the influence of the Devil and sets things back to the way he wants them.

Remember, Adam disobeyed a direct order from God, and that led to centuries of pain for mankind before God will purge the universe of all those who refuse to obey him and thus usher in an joyous life for all still living -- living according to God's original plan, obeying his laws, laws which restrain us from doing that which is bad for us or others.

The reason things are so bad now and God is allowing it is to teach us that our ways (taught by the Devil) lead only to grief, that we should do things his way.