Aliens, aliens, wherefore art thou?

What if E.T can't phone home because his species wiped themselves out before he could dial out. Lol. Source: www.shmoop.com

Lets face it, watching/reading world news has become super depressing. There is so much wrong with the world and faith in humanity is at quite a low. Before you "glass half full" kinda folk start calling me out for not focusing on the good in humanity, have  a little read about what Physicist Brian Cox has to say about why we haven't seen the real E.T feature in the news. The story was featured on www.iflscience.com in 2016 but is still on my mind: 

http://www.iflscience.com/space/brian-cox-explains-why-we-havent-seen-aliens-yet-and-it-isnt-pretty/

Let me put this into context. We have the capability to destroy ourselves. It is not absurd to theorize  that every civilization has the potential to progress to the point where they can destroy themselves. Island Biogeography teaches us that if the species immigration rate increases, then so does the rate of extinction. Now I am not talking about immigration into a country but rather the increase in population on earth due to the exponential increase in birth rate. Could life on a planet such as Keple-22b have died out because of the dominant species inability to work together despite having the technology to prevent their own extinction?

Kepler-22b identified as a planet in the "habitable zone". Source: https://en.wikipedia.org

There are billions too many people on the earth. Billions of individuals with individual thoughts and goals and likes and dislikes. Billions of people that would need to work together to deal with a mass extinction threat. Brian Cox has related this to other species on other plants and theorizes that other civilizations would need to also work together to annihilate a global threat and this is not likely to happen.

The question is, if we are faced with such a threat (and there are plenty reasons to believe that we already face the threat of mass extinction), are you a "glass half full kinda person"?

As for the aliens, E.T may have been out there but probably wasn't a team player so he didn't mobilize with the rest of his species to progress past internal conflict.