I don't see it. In the cosmic scheme of things we are simply non-players. I don't see that changing in the future for numerous reasons not the least of which is our space-time resource restrictions. We don't have the access to enough time-space to make a difference to the universe and if we ever do (gain sufficient access) we will have evolved beyond anything resembling human beings long before then. That's just my opinion of course.
We are Non-players, only if, what is coming here is outside or sphere of influence? Well current and public understanding is, a manned mission of exploration, to other Planets, other than the moon has never happened. But the potential exists, still for us to explore further in the future. That is my basic argument.
But how do we know for sure "ET" is not close by or residing and living and hiding out somewhere on this planet?
There is six billion of us humans living on the planet. What if. Say, the're is a race of beings ( low in number) hiding out on this planet. Would they fear extinction ( IF THEY EXPOSED THEMSELVES TO US OPENLY) Well, I would fear it, if we in the minority and not the majority.
Their technology, is far more advanced, to human technology, but is it indestructible technology? There is reports of Jet fighters getting close to the UFO's.. The UFO's flew away and in a hurry sometimes and some reports claim the UFO'S were disappearing and hiding, when the jets approached, but reappeared, when they Jet fighters came back to base.
While this not conclusive of anything or prove of why they took action or moved away > maybe it is a clue? UFO'S can be damaged and that is a good reason for UFO'S here to fly away when approached by a plane carrying weaponry. There is no evidence, if the UFO'S Attacked us, they could resist or weaponry? UFO'S do seem to be made of some type of metal? That could be damaged when fired upon?
We have a number of planets within our solar system. Nine and the're is possibility of a tenth, yet unfound. The scientific mainstream view is, well the claim is, all these planet's are too hazard for life, as we know it. As we know it> (Exactly) Some of the occupants of these craft, while they seem to have a Similar body shape to us, they might breath a different atmosphere to us or have adapted to an extreme hot climate or more extreme colder planet? Without having a set foot on these planets or at least sent a probe that can explore the landscape of these planets. I Still will remain open minded to the possibility, one of these planets in our solar system having intelligent life, beside us, of course. While it nice to speculate here> UFO's are occupied by Alien-pilots that have travelled the speed of light from the universe to here. I think it more likely is, they are close by (on the planet) or located somewhere within our solar system (one of the nine planets) So my theory is> They would fear a developing and yet aggressive species that is relatively close by to them and could have Potential or the ability, in 100 to 200 years, to come to their world and cause harm?