Liu Cixin's Postulate
There are many ideas about why it is that we find ourselves alone in our stellar neighborhood (and indeed, may find ourselves alone in the galaxy). The phenomenon itself is called the
Fermi Paradox, which like all physical paradoxes is a bit of a misnomer. It's more of an oddity, really, given what little we know about the probabilities involved we'd intuitively expect the cosmos to look different than it does.
From
this New Yorker article about the geopolitical stance of the most successful science fiction writer of our time:
Tech billionaires are still looking for scientists to help them break out of
the computer simulation that they suppose is our world. It’s difficult to look at this world view without taking the personal perspective of the believer into account, but let’s examine these claims on their own merits first.