Fermi paradox

The Fermi paradox is the discrepancy between the lack of conclusive evidence of advanced extraterrestrial life and the apparently high likelihood of its existence. As a 2015 article put it, "If life is so easy, someone from somewhere must have come calling by now."

...

"But where is everybody?"

Sci-fi writer Andy Weir says in his interview with Adam Grant (link 21:45):

"the nearest life might be like two million light years away"
"They are too far away"

I totally agree with this view.

There are 200 billion to 2 trillion galaxies in the observable universe.
Each galaxy has 100 billion stars.
Solar system is just a speck in the Milky Way Galaxy.
Nearest star to the Sun, Proxima Centauri, is 4.2 light-years away.

It is indeed too far away. Without factoring all the theories why we haven't found aliens, the distance alone is the greatest factor of all in my opinion.