Here is a pre-caffeine thought...
What if the real answer is that we are the first inhabited planet and that all of the extraterrestrials they are looking for don’t exist yet because we are the ones that will eventually colonize the universe.
Ah, time for more caffeine Dutch Boy :)
I have suggested this many times to people.
It is funny that the same people who can easily accept, rightly or wrongly,the evolutionary theory that the entire species of Homo Sapiens on earth came from one single ancestor — Lucy or whoever is in vogue these days — the first ever Homo Sapien after the missing link that evolved into modern Homo Sapiens...
Long sentence, anyway it is funny that these same people who readily accept we have a common evolutionary ancestor, cannot possibly accept that perhaps whatever life will be spread throughout the Universe could come from a single solitary source, man on earth. They just assume something must be out there because the Universe is so vast that other happy accidents just must have occurred. No application of logic whatsoever.