The thing that I worry about most that may or may not be true is that perhaps the spontaneous transformation from non-living matter to living matter is extraordinarily unlikely. We know that it has happened once. But what if we gain lots of evidence over the next few decades that it happens very rarely.
In my lifetime we can expect to examine the surface of Mars, and the moons of the gas giants in some detail. We can also expect to be able to image extra-solar planets within a few tens of light years to resolutions where we would be able to detect evidence of large scale biological activity.
What if none of these indicate any life whatsoever? What does that do to our scientific belief that life did arise spontaneously. It should not change it, but it will make it harder to defend against non-scientific attacks. And wouldn't it sadden us immensely if we were to discover that there is a vanishing small probability that life will arise even once in any given galaxy.
Being alone in this solar system will not be such a such a shock, but alone in the galaxy, or worse alone in the universe would, I think, drive us to despair, and back towards religion as our salve.