The Premise is that due to blind faith (ISIS is a case in point) or due to greed or insanity (North Korea is a case in point) new civilizations in their forward march destroy themselves in midterm before they are fully evolved or civilized.
We are now in this current threshold of self destruction.
My alien theory (I strongly believe they visited us in 1947, to investigate, two years after the Atomic Bomb Explosion) that they visited us but left convinced that we were not mature enough to interact with them.
Additionally Area 51 was not evolved to its present level of sophistication, then.
It was built after the possible crash of alien spaceship with more advanced technology.
I believe the alien spaceship was brought down by hostile fire.
By Nigel Calder and John Newell
The Lifespan of Advanced Civilizations
A very short lifespan for advanced civilizations may be a realistic probability because as our own case shows, technology mushrooms very rapidly and is accompanied by many dangerous effects such as;
2. Depletion of natural resources
3. Pollution and worse of all
4. Rapid escalation of nuclear stockpiles which can easily reach the level where they are capable of wiping out the whole population of a planet.
By the same token, if we were to find significant number of other advanced civilizations in our galaxy it would mean that some at least had been able to overcome the dangers that are now looming over our own civilizations.
If they have reached this advanced stage, it would mean that they have been able discard all of their animistic (BARBARISM) attributes such as materialism, selfishness, territoriality, dominance over others and killing instincts which in a technological civilizations are likely to lead to self destruction.
They would have been able to to mature into higher levels of cosmic intelligence characterized by spirituality, altruism, respect of others, adherence to peace and love for each other.
Joining such a galactic society would indeed be a colossal step forward in the intellectual and ethical evolution of our civilization.
This might also be the reason why we have not yet heard from any such advanced civilizations as may exist.
There must be a galactic rule that says that before a new civilization is invited to join the galactic society it must show that it is able to overcome the major crisis that probably befall all new technological civilizations.
Since we are still in the midst of this evolutionary problem, there may be advanced civilizations waiting to see how we do before inviting us to join the galactic society of advanced civilizations.