The proliferation of planet discoveries now makes the question of the absence of aliens a lot more pointed. There now seem to be billions and billions of planets, many of them likely rather Earthlike, so where (as Fermi asked) are all the aliens?
I asked this question of a deep thinker I know.
His opinion: "It probably means we will destroy this place in the next few hundred years."
There is no shortage of evidence thaat we aren't smart enough to handle the power technology has given us to screw up.