Personally I think that it’s just a case of
Space is big. You just won’t believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it’s a long way down the road to the chemist’s, but that’s just peanuts to space.
It may be teeming with life, but detecting it (or others detecting us) is just really hard. And the speed-of-light barrier doesn’t help either.
But hey, here’s another (somewhat darker, depending on how you look at it) idea that I haven’t seen anyone talk about.
See, when you get right down to it, all that we humans do is to try and generate pleasure and avoid pain. All our struggles are really directed to this end goal. We might think that we’re trying to explore the vast mysteries of space, but really we’re just after the high that comes with a new discovery.
So what happens when we can get it directly? As our technology advances, eventually we should be able to directly interface with our minds. And then… well… here’s a concept: The Pleasure Pod.
Take one human, and discard all the unnecessary parts. Basically leave just the brain and maybe some of the spinal cord. Put it in a jar with life support and add electrodes to all the right places. Stimulate the brain to produce the maximum amount of pleasure and leave it there for eternity.
Sure, you’ll also need a flock of robots that tend to the jars and maybe relocate the whole facility to a new star system once every few billion years, but that’s also doable.
Aaand that’s where everyone is. Once the Pleasure Pod of Immortality becomes available, it kinda becomes pointless to try and do anything else.
Some people might disagree and think that such a pod would be very unpleasant or unsatisfying, but by definition it wouldn’t. Entering it would be the most awesomest thing anyone could ever do.