ET won't show up as long as we are a species bent on self destruction.
I too, am in the crowd that believe that God has a plan for the universe and to be naive to think we are alone is to put your head in the sand to the power and possibilities the power of God would have across the universe.
Why not, do you think they are satisfied to wait until we blow each other into oblivion so they don't have to get their tentacles dirty slaughtering us? :)
I guess Europeans could have waited until the American Indians went the way of the Mayans, but it is a trait of advanced societies to explore and conquer. Logically an advanced ET would also be impatient and just invade as soon as they felt that they could get away with it.